THE  LIBRARY 

OF 

THE  UNIVERSITY 

OF  CALIFORNIA 

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H-t^ayV-    2  <?:./// 7. 


S*3i 


DIESEL     ENGINES 

FOR 

LAND    AND    MARINE    WORK 


DIESEL    ENGINES 

FOR 

LAND  AND  MARINE  WORK 

By    A.    P.    CHALKLEY 

B.Sc.  (LoND.),  A.M.Inst.C.E.,   A.I.E.E. 
WITH  AX  INTRODUCTORY  CHAPTER  BY  THE  LATE 

DR.     RUDOLF    DIESEL 


FOURTH  EDITION,   REVISED   AND  ENLARGED 


^=uwm!Vx 


NEW  YORK 

D.   VAN   NOSTRAND  COMPAIMY 

25  PARK  PLACE 
1916 


En.'rineeiiog 
library 

C36dL 


PREFACE 

The  interest  which  has  been  roused  in  this  country  over  the 

Diesel  motor  in  the  last  two  years  is  remarkable  for  its 

spontaneity  and  its  widespread  character.     The  reason  is 

not  far  to  seek.     The  questions  involved  are  not  merely 

technical,  but  of  far-reaching  commercial  importance,  and 

hence  are  by  no  means  Umited  in  their  discussion  to  the 

engineering  community.     The  Author  has  kept  this  point 

in  mind  in  dealing  with  the  subject  and  has  endeavoured  to 

render  the  book  suitable  to  all  those  who,  for  widely  differing 

reasons,  find  it  necessary  to  become  acquainted  with  the 

Diesel  engine,  and  it  is  with  intent  that  certain  elementary 

matters  have  been  included  to  aid  the  non-technical  reader. 

Hitherto,  no  book  has  been  published  dealing  solely  with 

this  type  of  motor,  but  it  is  hardly  necessary  to  say  that  the 

importance  it  has  now  attained  is  more  than  sufficient  to 

warrant  such  an  undertaldng. 
1  ... 

In  science,  it  is  sometimes  possible,  in  taldng  a  wide 

survey,  to  arrive  at  an  approximate  idea  as  to  the  probable 

future    developments    in    any    particular    direction.     The 

general  adoption  of  Diesel  engines  on  land  is  assured,  and, 

as  already  there  are  some  300  vessels  in  ser\dce  propelled  by 

these  machines,  it  wpuld  seem  safe  to  predict  that  a  large 

degree  of  success  will  be   obtained  at  sea,  particularly   as 

.^  the  very  desirable  probationary  period,  necessary  in  any 

"^  engineering  development  for  the  gathering  of  experience,  is 

.   nearly  at  an  end.     Should  the  expectations  which  have  been 

^-  formed  be  but  partially  realized,  the  effect  of    the  intro- 

'^"duction  of  the  Diesel  motor  would  still  perhaps  be  more 

V 


vi  PREFACE 

important  than  that  produced  by  any  other  recent  invention 
in  engineering  science. 

The  Author  has  received  much  help  from  various  manu' 
facturers  to  whom  reference  is  made  in  the  text.  To  Dr. 
Ernst  Miiller  he  would  also  wish  to  express  his  indebtedness, 
and  is  particularly  grateful  for  the  kindness  Dr.  Diesel  has 
shown  him,  and  the  interest  he  has  taken  in  the  preparation 
of  the  book. 

A.     P.    CHALKLEY. 

London, 

December,  1911. 


PREFACE  TO  THE  FOURTH   EDITION 

The  present  volume  represents  the  second  complete  re\nsion 
since  the  a\  ork  was  first  issued,  both  of  which  are  rendered 
essential  by  the  rapid  strides  that  were  made  in  design  and 
construction  of  the  Diesel  engine,  more  particularly  for 
marine  '\\'ork. 

Whilst  practice  has  become  standardized  to  a  certain 
extent  in  regard  to  the  manufacture  of  motors  of  the 
stationary  type,  it  is  still  felt  that  the  application  of  the 
engine  to  marine  work  is  in  its  infancy.  It  is,  therefore, 
in  the  section  of  the  book  dealing  with  Diesel  motors  for 
ships'  propulsion  that  the  greatest  additions  have  been  made. 
The  number  of  illustrations  has  been  nearly  doubled,  and 
besides  much  descriptive  matter  dealing  with  engines  of 
new  types  that  have  been  built  since  the  last  edition  was 
published,  there  is  an  additional  chapter  on  the  design  of 
Diesel  engines.  Beyond  this  the  whole  of  the  text  has  been 
carefully  revised,  and  considerable  additions  have  been 
made  in  the  body  of  the  work. 

In  pa}dng  a  respectful  tribute  to  the  memory  of  the  late 
Dr.  Diesel,  whose  friendship  to  me  was  more  valued  than 
he  knew,  I  feel  that  his  great  satisfaction  always  was  the 
fact  that  the  work  he  had  initiated  was  being  carried  on 
so  eagerly  and  successfully  throughout  the  whole  world. , 

A.  P.  CHALKLEY. 
London, 

October,  1914. 


CONTENTS 


PAGE 

Introduction  .........         i 


CHAPTER    I 

General  Theory  of  Heat  Engines,  with  Special  Refer- 
ence TO  Diesel  Engines    ......  9 


CHAPTER    II 
Action  and  Working  of  the  Diesel  Engine  ...        32 

CHAPTER    III 

Construction  of  the  Diesel  Engine        .  .  .  .57 

CHAPTER    IV 
Installing  and  Running  Diesel  Engines         .  .  .125 

CHAPTER    V 
Testing  Diesel  Engines  .  .  .  •  •  .146 

CHAPTER    VI 
Diesel  Engines  for  ]\Iakine  Work  .  .  .  .170 

ix 


X  CONTENTS 

CHAPTER    VII 

PAGE 

Construction  of  thk  Dtf.set<  Marine  Encune  .  .  .     206 

CHAPTER    VIII 

The  Design  of  Diesel  Engines        .....      302 

CHAPTER    IX 
The  Future  of  the  Diesel  Engine  .  .  .  .336 

Appendix  .........      345 

Index 365 


LIST    OF    ILLUSTRAilONS 


FIG.  TITLE                                                                 PAGE 

1.  Isothermal  and  Adiabatic  Curves  .           .           .           .12 

2.  Isothermal  and  Adiabatic  Curves  ....        12 

3.  Constant  Temperatiire  Cycle  Diagram.  .          .          .15 

4.  Constant  Voliune  Cj'cle  Diagram  .           .           .           .17 

5.  Constant  Pressure  Cycle  Diagram         .  .           .           .19 

6.  Diesel  Cycle  Diagrain  .           .           .           .           .           .21 

7.  Typical  Indicator  Cards  with  various  Diesel  Engines    .        29 

8.  Indicator    Cards    of    Four-Cylinder    800    B.H.P.    Sulzer 

Two-Cycle  Marine  Diesel  Motor        ....        30 

9.  Simultaneous    Indicator    Cards    for    Six-Cylinder    Fonr- 

Cycle  Marine  Diesel  Engine     .  .  .  .  .31 

10.  Diagram  showing  action  of  Diesel  Engine    .  .           .        34 

11.  Diagram  showing  action  of  Diesel  Engine    ...        34 

12.  Diagram  showing  action  of  Diesel  Engine    ...        34 

13.  Two-Stroke  Cycle  Diagram  .....        38 

14.  General  Arrangement  Plan  of  Diesel  Plant  .           .        00 

15.  Ditto— Elevation 60 

16.  Longitudinal  Section  of  M.A.X.  Diesel  Engine       facing       62 

17.  Transverse  Section  of  M.A.X.  Diesel  Engine  ,,            62 

18.  1,000  H.P.  M.A.N.  Diesel  Engine         .  .                „            62 

19.  880  H.P.  M.A.N.  Diesel  Engine  .           .           .           .64 

20.  Diagram    sho\\-ing    Arrangement    of    Cams    with    Diesel 

Engine  .........        66 

21.  Fuel  Inlet  Valve,  Lever  and  Cam        ....        67 

22.  Details  of  Fuel  Inlet  Valve  (Carels'  Type)  .  facing       68 

23.  Arrangement  of  Fuel  Admission  when  using  Tar  Oil     .        69 

24.  Details  of  Fuel  Valve  of  Hick,  Hargreaves  Diesel  Motor       70 

25.  Arrangement  of  Jointed  Valve  Lever  for  easy  dismantling      71 


LIST   OF    ILLUSTRATIONS 


nC.  TITLE  TAGE 

26.  Fuel  Inlet  Valve  and  Pulveriser  ....        72 

27.  Details  of  Fuel  Inlet  Valve  of  Deutz  Engine         .  .        73 

28.  Fuel  Inlet  Valve  of  Aktiebolaget  Diesels  IMotorer  Type       74 

29.  Mouthpiece  or  Bottom  Part  of  Pulveriser    .  .           .75 

30.  Diagram  showing  Action  of  Pulveriser  ...        76 

31.  Air  Inlet  and  Exhaust  Valves  (in  section)  .  .           .77 

32.  Details  of  Suction  and  Exhaust  Valves  of  Carels'  Four- 

CycleLand  Motor 78 

33.  Exhaust  Valve  (section)       ......        79 

34.  Arrangement  of  Governor  and  Fuel  Valve  of  ]Mirrlees, 

Bickerton  &  Day  Type  ...... 

35.  Fuel  Pump  (Willans  &  Robinson  Tj'pe)        .  .  . 

36.  ArrangeiTient  for  ControlUng  Fuel  and  Injection  Air 

37.  Front  Elevation  of  JVIirrlees  Diesel  Engine  .  facirg 

38.  Side  Elevation  of  ^Nlirrlees  Diesel  Engine      .  ,, 

39.  Deutz  Three-Cylinder  Vertical  Engine. 

40.  Longitudinal  Section  of  80  H.P.  Nederlandsche  Fabriek 

Engine  .......  facing 

41.  Transverse  Section  of  80  H.P.  Engine  .  ,, 

42.  Plan  of  80  H.P.  Engine      . 

43.  Arrangement  of  Air  Inlet   . 

44.  Section  of  Fuel  Piuup 

45.  General  Arrangement  of  Carels'  Four-Stroke  Stationary 

]\Iotor  with  Horizontal  Tliree-Stage  Compressor  facing 

46.  Method   of   removing   Piston   in   Nederlandsche   Fabriek 

Engine  ........ 

47.  Nederlandsche  Fabriek  Engine     ..... 

48.  End  Section  of  600  B.H.P.  Four-Cycle  Engine     . 

49.  Carels'  vSlow  Speed  Engine.  .  .  .  facing 

50.  Front  Section  of  600  B.H.P.  High  Speed  Engine  (Ned. 

Fab.)      .......  facing 

51.  200    H.P.     Sulzer    High-Speed    Four-Cycle    Stationary 

Engine  .......  facing 

52.  General     Arrangement     Plans     of     Two-Cylinder   Hick, 

Hargreaves    Motor,    16   in.    diameter,    19   in.    stroke, 
speed  250  r.p.m.     .....  facing 

53.  Burmeister  &  "Wain  High-Speed  Diesel  Engine  ,, 


SO 

82 
85 


86 

87 
87 
88 
89 
90 

90 

91 
92 
95 
93 

96 

96 


96 
98 


LIST  OF  ILLUSTRATIONS  xiii 

ylG.  TITLE  PAGE 

54.  Carels'  High  Speed  Engine            .           .           .            facing  98 

55.  Sulzer  High  Speed  Engine             .....  99 

56.  Section  through  High  Speed  Engine  and  Air  Pump      .  101 

57.  Dotiils  of  M.A.N.  Horizontal  Engine  .           .            facing  102 

58.  „  „  „  „  „  .  „  102 

59.  800  B.H.P.  Horizontal  Diesel  Engine  .  „  104 

60.  50  H.P.  Dautz  Diesel  Engine 105 

61.  Sulzer  Two-Cycle  2,400  B.H.P.  Engine  .  facing  108 

62.  Outline  Dimension  Drawing  of  2,400  B.H.P.  Engine     .  109 

63.  1,500  B.H.P.  Sulz-r  Two-Cycle  Engine  with  Port  Scaveng- 

ing   110 

64.  Section   tlirough  Cylinder  of    Sulz?r    Two-Cycle    Motor, 

showing  Auxiliary  Scavenge  Ports  .  .  .  .111 

65.  Details  of  Scavenge  Valve  of  Cards'  Two-Cycle  3Iotor       112 

66.  Carels'  Two-Cycle  Stationary  Motor  (New  Tj^e)  facing     114 

67.  Plan  of  Carels'  Two-Cycle  Stationary  ]Motor  (New  Type) 

facing     114 

68.  1,000  H.P.  Two-Cycle  Diesel  Engine    .  .  .  .114 

69.  Elevation  of  Carels'  Two-Stroke  Stationary  ]\Iotor  (New 

Type)     .......  facing     114 

70.  Details  of  Scavenge  Puinp  and  Air  Compressor  for  Carels' 

Two-Stroke  Stationary  Motor  (New  Type)  facing     114 

71.  Carels' Tsvo-Cycle  Sbatio:iiry  E-igLn3  of  1,000  H.P.     ,,  114 

72.  1,030  H.P.  Krupp  Two-Cycle  Motor.     Speed,  150  r.p.m. 

facing     114 

73.  Rsavell  Quadruplex  Compressor  .  .  .  .116 

74.  Section  of  Qaadraplex  Compressor       .  .  .  .117 

75.  Reavell's  Coinpressor  ....  facing     119 

76.  Section  of  Three-Stage   Vertical  Compressor   for   Diesel 

Engines  .  .  .  .  .  .  .  .118 

77.  General   Arrangement   of   Compressor   for   Carels'    1,500 

H.P.  Two-Cj'cle  Marine  Engine         .  .  facing     121 

78.  ^Marine  TyjDe  Compressor     .  .  .  .  ,,  122 

79.  Diagram  of  Vickers'   Solid  Injection  System  .  .123 

80.  Sketch  showing  Solid  Injection  Arrangement         .  .121 

81.  Outline  Drawing  of  Sulzer  Four-Cycle  Engines  (to  corre- 

s^iond  with  Table  of  Diniensions)     .  .  .  .127 


xiv  LIST  OF   ILLUSTRATIONS 

FIG.  TITLE  PAGE 

82.  Curve  showing  Fuel  Consiunption       .  .  .  .151 

83.  Curve  showing  Fuel  Consiunption       .  .  .  .156 

84.  Engine-room  Arrangement     of     Motor-ship     equipped 

with  a  2,000  H.P.  Two-Cycle  Engine        .  facing     182 

85.  Details  of  one  of  the  two  Scavenge  Pmnps  for   1,500 

B.H.P.  Carels'  Type  Marine  Diesel  Engine        .  .188 

86.  Diagram  of  Position  of  Valves  and  Piston  in  Two-Cycle 

Engine  (to  show  working)        .  .  .  .  .190 

87.  Two-Cj'cle  Engine  with  Scavenge  Ports  instead  of  Valves     191 

88.  Auxiliary    Compressor    and    Dynamo  driven  by  Diesel 

Engine,  installed  in  a  Motor  Sliip    .  .  .  .196 

89.  Sulzer  Auxiliary  Ship's  Set 197 

90.  2,000  H.P.   Single    Cylinder    Two-Cycle    Double-Acting 

Diesel  Engine  .....  facing     205 

91.  Sectional  Elevation  of  Two-Cj'cle  Sulzer  ]Marine  Engine     207 

92.  General    Arrangement   of    small   vessel  equipped  with 

Sulzer  Diesel  Engine        ......      208 

93.  General  Arrangement  of  Diesel  Ship  showing  Auxiliaries     209 

94.  General  Arrangement  Plan  of  Torpedo  Boat  with  Sulzer 

Engines  .  .  .  .  .  .  .  .211 

95.  Ditto  for  Submarines  .  .  .  .  .  .211 

96.  Sulzer  Direct  Reversible  Marine  Diesel  Engine  ;  a  type 

used  for  relatively  small  powers       .  .  .  .213 

97.  Svilzer  Marine  Engine.     Front  View  ....      214 

98.  Svilzer  Marine  Engine.     Back  View    .  .  .  .215 

99.  Arrangement  of  Scavenge  Pump  with  Sulzer  Engine  .      217 

100.  Arrangement  of  Scavenging  Ports       ,  .  .  .218 

101.  600   B.H.P.    Sulzer  High-Speed  Marine   Diesel   Engine     221 

102.  Sulzer  Marine  Engine         ....  facing     222 

103.  Sulzer  Two-Cycle  Submarine  Motor  of  600  B.H.P.     „         222 

104.  1,000  H.P.  Carels'  Diesel  Marine  Engine    .  .  .224 

105.  View  of  Engine-Room  of  M.S.  France  with  two  Schneider- 

Carels'  Motors  of  900  B.H.P.  at  230  r.p.m.      .  .     226 

106.  Scavenge  Pump  or  Compressor  for  900  H.P.  Two-Cycle 

Engine  at  230  r.p.m 227 

107.  1,500  B.H.P.  Carels'  Type  ]\Iarine  Motor  :    End  View 

sho^^•ing  Scavenge  Piunp  .  .  .  facing     228 


LIST  OF  ILLUSTRATIONS  xv 

FIG .  TITLE  PAGE 

108.  INIarine  Diesel  Engine,  Carels'  Tj^pe    .           .            facing  228 

109.  Plan  of  1,500  H.P.  Cards'  Marine  Engine.                „  228 

110.  Sectional  Elevation  of  1,500  H.P.  Cards'  IVIarine  IMotor 

(New  Type)    ......           f (icing  228 

HI.      1,800  B.H.P.  Cards-Reiehersteig  Marine  Diesel  Engine. 

Speed,  90-100  r.p.m iacing  228 

112.  1,500  H.P.  Cards-Tecklenborg  Engine          .                „  228 

113.  800  H.P.  Carels-Westgarth  Engine      .  .  .  .229 

114.  End  View  of  800  H.P.  Carels'  Type  Two-Cycle  Marine 

Motor 231 

115.  General  Arrangement  of  Engine-room  of  Ship  equipi^ed 

with  Aktiebolaget  Diesels  Motorer  Engine          facing  232 

116.  800  B.H.P.  Polar  Marine  Engine        .  .  .  .235 

117.  Near  View   of  Cam  Shaft   of    800   H.P.   Polar   Diesel 

Marine  Engine         .......  237 

118.  850  B.H.P.  Polar  Two-Cycle  Reversible  Marine  Diesel 

Engine 239 

119.  Near   View    of   Cylinders    of    Polar    Marine   Engine    as 

installed 241 

120.  650   B.H.P.    Neptmie   Polar   Marine   Engine,    built   by 

Messrs.  Swan,  Hunter  &  Wigham  Richardson  facing  241 

121.  High-Speed  Reversible  Marine  Polar  Engine  for  Sub- 

marines and  Yachts         ......  242 

122.  Polar  Diesel  Marine  Engine        .....  243 

123.  Krupp  Two-Cycle  1,000  B.H.P.  Engine       .  .  .245 

124.  Diagram  showing  action  of  Cams  for  Krvipp's  Engine  246 

125.  Section  of  1,250  B.H.P.  Krupp  Engine       .  .  .248 

126.  1,250  B.H.P.  Krupp  Engine 249 

127.  Tops    of    two    1,259    H.P.    Krupp  Two-Cycle  Engines 

installed  in  Motor  Ship  .  .  .  .  .  .250 

128.  Reversing  Mechanism  of  Krupp  Engine      .            facing  252 

129.  1,250  B.H.P.  Krupp  Two-Cycle  Marine  Engine  .      „  252 

130.  Diagrammatic  Representation  of  Niirnberg  Two-Cycle 

Marine  Engine,  showing  Scavenge  Arrangements       .  253 

131.  Diagram   illustrating   Method    of    Reversing   Niirnberg 

Engine  .........  255 

132.  Sectional  Illustrations  of  Niii-nberg  Marine  Engine  facing  258 


PAGE 

259 

261 

facing 

262 

B       ,, 

262 

,, 

262 

facing 

264 

266 

facing 

268 

269 

271 

xvi  LIST  OF  ILLUSTRATIONS 

FIG.  TITLE 

133.  End  View  of  Niirnberg  Engine. 

134.  M.A.N.  900  H.P.  Submarine  Engine. 

135.  Standard  Niirnberg  Marine  Engine     . 

136.  850  B.H.P.  Weser-Junkers  Marine  Diesel  Engine 

137.  850  B.H.P.  Weser- Junkers  Marine  Engine. 

138.  Tanner-Diesel  Engine  .... 

139.  Doxford  Diesel  Engine       .... 

140.  500  H.P.  Engine  for   Vulcanus  . 

141.  Engine-room  of  Vulcanus 

142.  Werlcspoor  Engine  of  250  B.H.P. 

143.  Werkspoor  1,100  B.H.P.  Diesel  Motor         .  facing     272 

144.  1,100  B.H.P.  Werkspoor  Engine  .  .  .  .272 

145.  Arrangement    of    Piston    Cooling    in    XN'erkspoor    1,100 

B.H.P.  Marine  Motor 273 

146.  Section  of  Werkspoor  1,100  B.H.P.  Four-Cycle  Marine 

Motor 274 

147.  Top  View  of  two  1,100  B.H.P.  Werkspoor  Fonr-Cycle 

Engines  in  the  Motor  Sliip  Emanuel  Nobel       .  .      276 

148.  Gusto  Two-Cycle  Marine  Motor  .  .  .  .278 

149.  Elevation  and  Section  of  Gusto  Diesel  Motor     .  .      279 

150.  M.A.N.  High-Speed  Engine 282 

151.  1,250  I.H.P.  Burmeister  &  Wain  Engine    .  faciiig     283 

152.  1,000  B.H.P.  Burmeister  &  Wain  Marine  Diesel  Engine^  284 

153.  Interior  of  Engine-room  of  Motor  Ship  with  two  Bur- 

meister &  Wain  Diesel  Engines        .  .  .  .285 

154.  Starting,  Inlet  and  Fuel  Valves  of  2,000  I.H.P.   Bur- 

meister &  Wain  Marine  Diesel  Engine      .  facing     286 

155.  Section  of  Six-Cylinder  Biu-meister  &  ^Vain  2,000  I.H.P. 

Marine  Engine         .  .  .  .  .  .  .288 

156.  2,000  I.H.P.  Burmsister  &  Wain  Marine  Diesel  Engine, 

showing  intermediate  Shaft  and  Push  Rods  for  oper- 
ating the  Valves  .  .  .  .  .  .299 

157.  Kolomna  Diesel  Engine     ......      292 

158.  Kolomna  Diesel  Engine     ......      293 

159.  100  H.P.  Daimler  Diesel  Four-Cycle  Rever.sibk>  Marine 

Engine  .........      295 

160.  Ki-upp  Fovu'-Cycle  Marine  :\Iotor         ....      297 


LIST   OF  ILLUSTRATIONS 


xvii 


FIG.  TITLE  PAGE 

161.  Junkers  100  H.P.  Marine  Motor         ,  ,  .  .298 

162.  150  H.P.  Two-Cyele  American  Diesel  Marine  Engine     .  299 

163.  150  H.P.  Kind  Two-Cj'cle  Marine  Diesel  Engine          .  301 

164.  Details  of  Cylinder  Cover  of  Hick,  Hargreaves  Motor   .  304 

165.  Details  of  Piston  of  Hick,  Hargreaves  Diesel  Motor   .  307 

166.  Compression  Curves  in  Two-Stage  Compressor     .           .  326 

167.  Diagrammatic  Representation  of  Two-Stage  Compressor  328 

168.  Diesel  Engine  Indicator  Diagram  with  Valve  Scavenging  331 

169.  Diagram  of  Engine  with  Port  Scavenging            .          .  3.32 

170.  Sulzer  Diesel  Locomotive  built  for  the  Prussian  State 

Railways         ••......      338 

171.  Diagram  ilkistrating  Arrangement     of     Sulzer     Diesel 

Locomotive     .  .  .  .  .  .  .  .339 

172.  Arrangement    of    Drive    for    Sulzcr-Diesel    Locomotive 

facing     340 
l.^ 
2 
3 
4. 
5-  Relative  to  Diesel's  Patent  Specification,  and  are  referred  to 

"I  in  the  Appendix. 

7 

8 

9 

10 


INTRODUCTION 

By   dr.   RUDOLF  DIESEL 

Very  willingly  do  I  accede  to  the  Author's  request  to  add 
an  introduction  to  this  book,  because  I  am  very  glad  that 
an  attempt  should  thus  be  made  to  present  the  subject  of 
the  Diesel  engine  in  a  concise  and  well-ordered  form,  in  view 
of  the  amount  of  scattered  literature  there  is  deahng  Avith 
the  question. 

Since  its  first  appearance  about  fourteen  years  ago,  many 
thousands  of  Diesel  engines  have  been  installed  in  all  kinds 
of  factories  in  all  industrial  countries,  and  also  in  the  re- 
motest corners  of  the  world  ;  proof  has  thus  been  obtained 
that  the  motor,  when  properly  installed,  is  a  reliable  machine, 
whose  operation  is  as  satisfactory  as  the  best  of  other  types 
of  engine,  and,  in  general,  simpler,  owing  to  the  absence  of 
all  auxiliary  plant,  and  because  the  fuel  can  be  employe:! 
directly  in  the  cylinder  of  the  motor  in  its  original  natural 
condition,  without  any  previous  transformatory  process. 

In  1897,  when  after  four  years  of  difficult  experimental 
work  I  completed  the  construction  of  the  first  commercially 
successful  motor  in  the  Augsburg  Works,  it  was  proclaimed 
by  the  numerous  engineering  and  scientific  committees  and 
deputations  from  various  countries,  who  tested  the  machine, 
that  a  higher  heat  efficiency  was  attained  by  it  than  with  any 
other  known  heat  engine.  As  a  result  of  subsequent  ex- 
perience in  practice,  and  the  gradual  improvement  in  the 
manufacture,  still  better  results  have  been  obtained,  and 
at  the  present  time  the  thermal  efficiency  the  motor  attains 
is  up  to  about  48  per  cent,  and  the  effective  efficiency  in 
some  cases  up  to  nearly  35  per  cent. 

'  B 


2  INTRODUCTION 

Technical  knowledge  and  science  are  always  progressing, 
and  in  later  days  these  figures  will  be  even  further  improved, 
but  in  the  present  state  of  our  knowledge  a  higher  efficiency 
cannot  be  reached  by  any  process  for  changing  heat  into 
work  ;  a  further  advance  seems  only  possible  by  a  new 
process  of  conversion,  with  an  essentially  novel  method  of 
operation  which  we  to-day  cannot  conceive. 

Therefore  the  Diesel  motor  is  the  engine  which  develops 
power  from  the  fuel  directly  in  the  cyhnder  without  any 
previous  transformatory  process,  and  in  as  efficient  a  manner 
as,  according  to  the  present  state  of  science,  seems  possible  ; 
it  is  therefore  the  simplest  and  at  the  same  time  the  most 
economical  power  machine. 

These  two  conditions  explain  its  success,  which  hes  in 
the  novel  principle  of  its  method  of  operation  and  not  in 
construction?.  1  improvements  or  alterations  to  earlier  engine 
types.  Naturally  the  questions  of  construction,  and  the 
careful  design  of  the  details,  are  of  considerable  moment  in 
a  Diesel  motor  as  in  every  engine  ;  but  they  are  not  the 
cause  of  the  great  importance  of  this  motor  in  the  world's 
industry. 

A  further  reason  for  this  importance  Ues  in  the  fact  that 
the  Diesel  engine  has  destroyed  the  monopoly  of  coal,  and 
has  in  the  most  general  way  solved  the  problem  of  the 
employment  of  hquid  fuel  for  motive  purposes.  The  Diesel 
motor  has  thus  become  in  relation  to  hquid  fuel,  what  the 
steam  and  gas  engine  are  to  coal,  but  in  a  simpler  and  more 
economical  manner  ;  it  has  by  this  means  doubled  the 
lesources  of  man  in  the  sphere  of  power  development,  and 
found  employment  for  a  product  of  nature  which  previously 
lay  idle. 

In  consequence  thereof  the  Diesel  motor  has  had  a 
far-reaching  effect  in  the  liquid  fuel  industry,  which  is 
now  progressing  in  a  way  that  could  not  previously  be 
anticipated.  I  cannot  here  enlarge  on  this  point,  but  it 
may  in  general  be  said  that  owing  to  the  interest  which  the 
petroleum  producers  have  taken  in  this  important  matter, 
new  weUs  are  being  constantly  opened  out,  and  fresh  develop- 


INTRODUCTION  3 

ments  inaugurated,  and  that  from  the  latest  geological 
researches  it  has  been  shown  that  there  is  probably  as  much, 
and  perhaps  more,  liquid  fuel  than  coal  in  the  earth,  and 
moreover  in  much  more  favourable  and  more  widely  distri- 
buted geographical  positions. 

That  the  undertakings  dependent  on  the  petroleum 
industry  have  been  equally  strongly  influenced  is  shown  by 
the  marked  development  which  in  quite  recent  times  has 
occurred  in  the  oil  transport  trade,  especially  the  great 
development  in  the  number  of  tank  vessels  which  themselves 
use  the  Diesel  motor  for  propulsion. 

But  the  influence  of  the  Diesel  engine  on  the  world's 
industry  does  not  end  here.  Already  in  the  year  1899  I 
employed  in  my  motor  the  by-products  from  the  distillation 
of  coal,  and  the  manufacture  of  coke — tar  or  creosote  oil — 
with  the  same  success  as  with  natural  liquid  fuel.  The 
quality  of  these  oils  was  however  generally  unsatisfactory 
for  use  in  Diesel  motors  and  subject  to  continual  variations. 
Only  recently  the  interested  chemical  industries  have  suc- 
ceeded in  getting  the  necessary  quality,  and  to-day  this  pro- 
duct enters  definitely  into  the  sphere  of  influence  of  the 
Diesel  motor. 

It  follows  therefore  that  this  engine  has  an  important 
influence  on  the  two  further  industries — ^gas  and  coke  manu- 
facture— from  which  the  by-products  have  now  become 
so  important  that  a  great  movement  is  beginning  in 
connexion  with  this  question.  It  is  impossible  further  to 
discuss  this  matter  here,  but  one  fact  arises  distinctly  from 
this  movement,  namely,  that  the  coal  which  appeared  to  be 
threatened  by  the  competition  of  Hquid  fuels  will,  on  the 
contrary,  enter  into  a  new  and  better  era  of  utilization 
through  the  Diesel  motor.  Since  tar  oil  can  be  employed 
three  to  five  times  more  efficiently  in  the  Diesel  motor  than 
coal  in  the  steam  engine,  it  follows  that  coal  can  be  much 
more  economically  utiHzed  when  it  is  not  burnt  barbarously 
under  boilers  or  grates,  but  converted  into  coke  and  tar 
by  distillation.  The  coke  is  then  employed  in  metallurgical 
work  and  for  all  heating  purposes  ;    the  valuable  products 


4  INTRODUCTION 

from  the  tar  must  be  extracted  and  used  in  the  chemical 
industries,  while  the  tar  oil,  and  its  combustible  derivatives, 
and  under  certain  circumstances  the  atr  itself,  can  be  put 
to  exceptionally  favourable  use  in  Diesel  motors. 

It  is,  therefore,  of  the  greatest  interest  to  employ  the 
largest  possible  amount  of  coal  in  this  refined  and  more 
economical  manner,  and  thus  both  coal  mining  and  the 
related  chemical  industry  come  within  the  influence  of  the 
Diesel  motor,  which  is  not  inimical  but  most  helpful  to  the 
development  of  the  coal  industry.  The  proper  evolution 
of  the  fuel  question  which  has  already  begun  and  is  now 
progressing  rapidly  is  as  follows  :  on  the  one  side  use  liquid 
fuel  in  Diesel  motors,  on  the  other  side,  gas  fuel,  also  in  the 
form  of  coke,  in  gas  motors  :  solid  fuel  should  not  be  employed 
at  all  for  power  production,  but  only  in  the  refined  form  of 
coke  for  all  other  uses  of  heat  in  metallurgy  and  heating. 

The  liquid  fuels  already  mentioned  by  no  means  exhaust 
the  list  of  fuel  which  may  be  used  for  Diesel  motors. 

It  is  well  known  that  lignite,  whose  production  is  about  10 
per  cent,  of  that  of  coal,  leaves  tar  on  dry  distillation  which 
when  worked  for  pure  paraffin  leaves  as  a  by-product  the  so- 
called  paraffin  oil.  Not  all  kinds  of  lignite  are  suitable  for 
this  purpose,  nevertheless  so  much  of  this  oil  is  produced 
that  up  to  now  it  has  supplied,  for  instance  in  Germany, 
a  very  large  proportion  of  the  demand  for  liquid  fuel  for 
Diesel  motors.  Further  there  are  to  be  considered  other 
products  available  in  smaller  but  noteworthy  quantities 
such  as  shale  oil,  etc.  ;  certain  countries,  as  for  instance 
France  and  Scotland,  have  large  quantities  of  them  and  they 
are  in  use  in  many  Diesel  engine  installations. 

But  it  is  not  yet  generally  known  that  it  is  possible  to 
use  animal  and  vegetable  oils  direct  in  Diesel  motors.  In 
1900  a  small  Diesel  engine  was  exhibited  at  the  Paris  exhibi- 
tion by  the  Otto  Company  which,  on  the  suggestion  of 
the  French  Government,  was  run  on  Arachide  oil,^  and 
operated  so  well  that  very  few  people  were  aware  of  the 
fact.  The  motor  was  built  for  ordinary  oils,  and  without  any 
^  Botanical  name  :  Arachis  hypogsea  Jj, 


INTRODUCTION  S 

modification  was  run  on  vegetable  oil.  I  have  recently  re- 
peated these  experiments  on  a  large  scale  with  full  success  and 
entire  confirmation  of  the  results  formeily  obtained.  The 
French  Government  had  in  mind  the  utilization  of  the  large 
quantities  of  arachide  or  ground  nuts  available  in  the  African 
colonies  and  easy  to  cultivate,  for,  by  this  means,  the 
colonies  can  be  provided  with  power  and  industries,  without 
the  necessity  of  importing  coal  or  liquid  fuel. 

Similar  experiments  have  also  been  made  in  St.  Peters- 
burg with  castor  oil  with  equal  success.  Even  animal  oils, 
such  as  fish  oil,  have  been  tried  with  perfect  success. 

If  at  present  the  applicability  of  vegetable  and  animal 
oils  to  Diesel  motors  seems  insignificant,  it  may  develop 
in  the  course  of  time  to  reach  an  importance  equal  to  that  of 
natural  liquid  fuels  and  tar  oil.  Twelve  years  ago  we  were 
no  more  advanced  with  the  tar  .oils  than  to-day  is  the  case 
with  the  vegetable  oils  ;  and  how  important  have  they  now 
become  ! 

We  cannot  predict  at  present  the  role  which  these  oils  will 
have  to  play  in  the  colonies  in  days  to  come.  However, 
they  give  the  certainty  that  motive  power  can  be  produced 
by  the  agricultural  transformation  of  the  heat  of  the  sun, 
even  when  our  total  natural  store  of  solid  and  liquid  fuel 
will    be    exhausted. 

Having  now  made  a  short  survey  of  the  importance  of 
the  Diesel  motor  to  the  world's  industry  in  general,  I  would 
add  a  few  words  concerning  its  importance  to  England  in 
particular.  The  following  three  facts  must  be  kept  in  mind 
for  consideration  : — 

1.  England  is  an  exclusively  coal -producing  country. 

2.  England  is    the    greatest   colonizing  country   in   the 

world. 

3.  England  is  the  greatest  marine  nation  in  the  world. 
(1)  England  possesses  (at  any  rate  up  to  now)  no  natural 

liquid  fuel,  and  is  a  purely  coal-producing  country  ;  owing 
to  this  fact  the  opinion  has  lately  been  frequently  and 
strongly  expressed  that  England  has  intrinsically  no  concern 
with  the  Diesel  motor,  and  that  it  is  against  her  most  Aatal 


6  INTRODUCTION 

interests  to  help  in  the  more  widespread  adoption  of  this 
engine,  since  she  would  neglect  her  own  wealth  of  coal  and 
would  render  herself  dependent  on  other  countries  by  the 
employment  of  liquid  fuel. 

Both  these  statements  are  wrong  and  the  reverse  is  true. 
It  is  in  England's  greatest  interest  that  the  coal -devouring 
steam  engine  should  be  replaced  by  the  economical  Diesel 
motor,  and  particularly  so  as  by  such  a  change,  economies  can 
be  effected  in  her  most  important  wealth,  the  coal — and  the 
life  of  the  mines  prolonged  ;  further,  because  it  improves  in  a 
most  rational  way  the  use  of  coal  and  the  results  of  the 
allied  chemical  industries,  in  utilizing  the  coal  in  the  refined 
manner  previously  mentioned  ;  finally,  because  by  this 
method  of  utilizing  the  coal  (that  is  through  the  employ- 
ment of  tar  and  tar  oils  in  Diesel  motors),  England  becomes 
free  and  independent  of  foreign  countries  for  the  supply  of  her 
liquid  fuel. 

(2)  The  extent  to  which  England  may  help  her  colonies 
through  the  Diesel  motor  can,  as  yet,  hardly  be  conceived  ; 
even  when  using  natural  mineral  oils  alone,  the  Diesel  motor 
is  a  machine  essentially  adapted  for  work  in  the  colonies, 
as  only  from  one-fourth  to  one-sixth  part  of  the  weight  of 
fuel  has  to  be  transported  to  the  colony  and  into  the  interior, 
as  compared  with  a  steam  engine  ;  because  in  the  colonies 
the  freight  charges  for  the  fuel  are  generally  the 
decichng  factor  in  the  profitableness  of  power  plants. 
Further,  because  the  transport  of  this  liquid  fuel  is  in- 
comparably easier  and  more  convenient  than  coal,  and 
finally  because  the  difficulties  of  running  a  boiler  installation 
— particularly  marked  in  the  hinterland — put  the  steam 
plant  out  of  question. 

It  may  be  mentioned  in  this  connexion  that  a  pipe  line 
for  crude  petroleum  400  kilometres  long  will  be  laid  from 
Matadi  to  Leopoldville  on  the  Congo,  bj^  means  of  which 
this  immense  country  will  be  provided  with  a  constant 
source  of  liquid  fuel,  which  will  give  its  essential  living 
element — the  motive  power — to  agricultural  and  transport 
enterprises,  and  other    industries  about    to  be   established. 


INTRODUCTION  7 

This  wonderful  example  should  be  followed  in  the  English 
colonies  ;  it  is  unnecessary  to  follow  the  far-reaching  effects 
of  such  a  course  on  the  prosperity  of  the  colonies. 

When  it  is  remembered  that,  as  previously  mentioned,  the 
Diesel  motor  can  also  run  on  vegetable  oils,  it  is  not  difficult 
to  see  that  this  fact  opens  out  a  new  prospect  for  the  pros- 
perity and  industry  of  the  colonies,  a  fact  which  is  of  great:r 
importance  to  England  than  to  any  other  country  owing  to 
the  large  number  of  its  possessions.  On  this  point  and  as 
quickly  as  possible  the  problem  should  be  tackled  ;  the 
Diesel  motor  can  be  driven  by  the  colonies'  own  products, 
and  thus  in  a  great  degree  can  aid  in  the  development 
of  the  agriculture  in  the  country  in  which  it  operates. 
This  sounds  to-day  somewhat  as  a  dream  of  the  future, 
but  I  venture  the  prophecy  with  entire  conviction  that 
this  method  of  the  employment  of  the  Diesel  motor  will 
in  days  to  come  attain  great  importance. 

(3)  Finally,  England  is  the  greatest  marine  power  in  the 
world. 

When  the  first  success  of  the  Diesel  motor  as  a  marine 
engine  became  known  in  England  last  year  ;  when  it  was 
realized  that  already  a  large  number  of  small  merchant  and 
naval  vessels  were  equipped  with  Diesel  engines,  and  that 
progress  was  gradually  being  made  on  a  larger  scale  ;  that 
already  large  American  liners  were  to  be  propelled  by 
Diesel  motors,  and  at  the  same  time  a  warship  was  in  con- 
struction to  be  equipped  with  a  very  large  Diesel  engine  ; 
then  there  was  much  stir  and  some  excitement  throughout 
the  country  which  is  still  fresh  in  the  mind. 

And  rightly  so  !  The  reports  of  satisfactory  sea  voyages 
with  Diesel  motors  under  very  bad  weather  conditions 
are  becoming  more  numerous.  The  ships'  captains  who 
have  Diesel  motors  in  their  ships  certify  to  their  great 
reliability  and  convenience  of  running,  and  figures  are 
published  showing  the  economy  effected  ;  it  can  no  longer  be 
doubted  that  in  this  direction  the  Diesel  motor  will  create 
one  of  the  greatest  evolutions  in  modern  industiy. 

That  the  greatest  shipping  nation  in  the  world  should  derive 


8  INTRODUCTION 

no  advantage  from  such  a  change  would  be  simply  impossible. 
England  is  bound,  in  the  face  of  competition  with  other 
countries,  to  take  full  advantage  of  this  new  departure. 

Finally,  a  few  words  on  the  manufacturing  : — The  Diesel 
motor  must  be  constructed  with  extreme  care,  and  the  best 
materials  employed  in  order  that  it  may  properly  fulfil  all 
its  capabilities  ;  only  the  best  and  most  completely  equipped 
works  can  build  it.  Fourteen  years  ago  there  were  very 
few  factories  which  were  able  to  undertake  its  construction, 
and  it  may  be  said  that  through  the  Diesel  engine 
the  manufacture  of  large  machines  has  been  raised  to  a 
higher  level,  in  the  same  way  as  the  manufacture  of  small 
machines  has  been  brought  on  new  lines  by  the  automobile 
engine. 

The  Diesel  motor  is  therefore  not  a  cheap  engine,  and 
I  would  add  a  warning  that  the  attempt  should  never  be 
made  to  try  to  build  it  cheaply,  by  unfinished  workmanship, 
particularly  for  export. 

Tliese  fundamental  conditions  regarding  the  construction 
of  the  Diesel  engine  are  no  disadvantage,  as  has  been  fre- 
quently proved  ;  on  the  contrary  they  are  precisely  the 
reason  of  its  strong  position  and  form  a  guarantee  of  its 
worth. 

Munich,  DIESEL. 

December,  1911, 


CHAPTER  J 

GENERAL   THEORY    OF    HEAT    ENGINES    WITH 
SPECIAL  REFERENCE  TO  DIESEL  ENGINES 

EXPANSION  OF  GASES — ADIABATIC  EXPANSION — ISOTHERMAL 
EXPANSION  —  WORKING  CYCLES — •  THERMO-DYNAMIC 
CYCLES— CONSTANT  TEMPERATURE  CYCLE —  CONSTANT 
VOLUME  CYCLE — CONSTANT  PRESSURE  CYCLE —  DIESEL 
ENGINE  CYCLE^REASONS  FOR  THE  HIGH  EFFICIENCY 
OF    THE    DIESEL    ENGINE. 

Expansion  of  Gases.- — Though  it  is  unnecessary  to  go 
fully  into  any  detail  regarding  the  theory  of  heat  engines, 
a  general  study  of  the  laws  governing  the  expansion  of 
gases,  and  the  theoretically  and  practically  attainable 
efficiencies  of  motors  working  on  gaseous  fuel,  is  desirable 
in  order  to  understand  the  action  of  the  Diesel  engine,  and 
the  reason  for  its  higher  efficiency  than  that  of  any  other 
heat  engine.  The  basis  of  the  various  formulae  quoted  in 
the  following  pages  will  be  found  in  any  text -book  on  heat 
engines,  and  elucidation  is  only  given  in  this  volume  where 
it  bears  directly  on  the  theory  of  the  Diesel  engine. 

In  a  consideration  of  the  expansion  of  gases  with  the 
consequeiit  production  of  work  there  is  always  a  definite 
relation,  for  the  same  weight  of  gas,  between  the  volume, 
pressure,  and  temperature  at  any  moment  during  the 
expansion,  and  this  relation  is  given  by  the  formula  PV=>;T 
where  P  =  absolute  pressure  in  lb.  per  square  foot. 
V  =  Volume  in  cubic  feet. 

T=  absolute  temperature  in  degrees  Fahrenheit. 

tf  —  constant. 


10      DIESEL  ENGINES  FOR  LAND  AND  MARINE  WORK 

and  of  course  the  same  formula  applies  for  other  units  (e.g. 
metric  units),  with  a  different  value  for  »/.  The  value  of 
t]  varies  with  different  gases,  and  it  is  in  fact  the  difference 
between  the  specific  heats  of  the  gas  at  constant  pressure, 
and  at  constant  volume  and  may  be  expressed  as 

'/  =  K^  —  K, 
where  K^  =  Specific    heat    of     gas    at    constant     pressure. 

K„  =  Specific  heat  of  gas  at  constant  volume. 
In  the  units  given  above,  for  air  Kp  =  184-7  K^  =  131-4  and 
>7  =  53-3.     In  the  formulae  which  follow,  it  will  be  seen 
that  the  ratio  of  the  two  specific  heats  is  of  importance  and 

this  ratio,  i.e.  — ^  is  usually  denoted  by  the  symbol  y  which 

for  air  is  1-405  and  for  other  gases  used  in  heat  engines  some- 
what less,  1-32  being  for  instance  a  fair  figure  for  lighting 
gas. 

Since  with  all  gases  PV  =  >/T,  it  is  evident  that  for  the 
same  quantity  of  gas  either  the  pressure,  volume,  or  tem- 
perature, is  determinate  if  the  two  other  values  be  known, 

P    Vi  PoVo 

i.e.  =  ^ — -"  where  Pi,  Vi,  and  Ti,    represent    respec- 

T^  Ta 

tively  the  pressure,  volume,  and  temperature  of  the  gas  in 
one  state  and  P2,  Vo  and  To  the  pressure,  volume,  and 
temperature  of  the  same  weight  of  gas  in  another  state. 

For  purposes  of  solving  the  problems  of  the  behaviour 
of  gases  during  expansion,  there  are  two  methods  of  expan- 
sion which  are  generally  considered,  neither  of  which  how- 
ever is  exactly  attained  in  actual  heat  engines.  These 
are  : — 

1.  Expansion  at  constant  pressure. 

2.  Expansion  in  which  the  pressure  and  volume  vary 
according  to  the  formula  PV"  =  constant 

Under  the  heading  (2)  come  the  two  special  cases  of 
expansion  which  are  of  the  most  importance  in  the  theory 
of  heat  engines,  namely  (a)  adiabatic  expansion  according 
to  the  formula  PV^=  constant,  and  (6)  isothermal  expan- 
sion, according  to  the  formula  PV  =  constant. 

Adiabatic   Expansion. — When  a   gas  expands  adiaba- 


GENERAL  THEORY  OF  HEAT  ENGINES    11 

tically  no  heat  is  lost  or  gained  during  the  expansion,  the 
whole  of  the  heat  being  employed  in  doing  external  work, 
and  it  is  evident  at  once  that  such  can  never  be  quite 
realized  in  practice.  The  relation  between  temperature  and 
volume  is  important  in  considering  the  question  of  the 
efficiencies  of  the  cycles  on  which  the  Diesel  and  other  heat 
engines  operate,  and  this  relation  may  be  arrived  at  as 
follows  : — 


(1) 

(2) 


)r  any 

gas 

P2V 

-  hence  P.T, 

=    P2T, 

v^  ■■•■ 

also  PiVi' 

^=P2V; 

>7  hei 

V2 
ice  _  = 

.Pi^ 
1    •  • 

P2^ 

Substitutir 

ig  (2) 

in  (1) 

P.T, 

:   =  PoTi 

X^ 

P^^ 

T, 

or  —  = 

P2 

1 
Pi^ 

P2^ 

■■.1. 

which 

is 

_P^ 

y 

—  1 

y 

P." 

y 

(3) 


and  in  a  similar  manner  it  may  be  shown  that 

'    (^) 


T2  ^  /v^Y 


Isothermal  Expansion. — In  isothermal  expansion  the 
temperature  of  the  gas  during  the  whole  expansion  remains 
unaltered,  and  hence  the  internal  energy  in  the  gas  itself 
remains  unaltered,  and  the  heat  given  to  the  gas  is  equiva- 
lent to  the  external  work  done.  In  this  expansion  from 
the  general  formula  PV  =  »/T,  since  T  is  constant  the  pres- 
sure must  vary  inversely  as  the  volume,  and  since  the  equa- 
tion  PV  =  constant   is  that   of  an  equilateral  hyperbola. 


12      DIESEL  ENGINES  FOR  LAND  AND  MARINE  WORK 

isothermal  expansion  is   sometimes   known   as   hyperbolic 
expansion. 

The  relation  between  isothermal  and  adiabatic  expansion 


Adia.ba.cic 


Fig.    1. — isothermal  and  Adiabatic  Ciu'ves. 

curves  is  readity  seen  on  a  pressure  volume  diagram,  Fig.  1, 
in   which  the  isothermal  is  above  the  adiabatic  line,  and 


Fig.   2. — Isothermal  and  Adiabatic  Curves. 


Fig,  2  shows  the  same  curves  during  compression  in  which 
the   adiabatic   is   above   the  isothermal.     During  adiabatic 


GENERAL  THEORY   OF   HEAT   ENGINES  13 

compression  the  temperature  after  compression  must  rise, 
since 

T         /P  \  ">'~  ^ 

—  =  (  —  )    y     and  this  must  be  greater  than  1. 

It  follows  therefore  that  comparing  adiabatic  and  iso- 
thermal compression  a  higher  temperature  may  be  reached 
with  the  former  than  with  the  latter  (in  which  there  is 
no  rise  of  temperature),  employing  the  same  compression 
pressure,  wliich  is  the  reason  of  gas  engines  working  with 
adiabatic  compression  rather  than  isothermal,  since  a  high 
temperature  is  required  with  a  minimum  pressure. 

Working  Cycles. — All  heat  engines  work  through  a 
mechanical  C3'cle  of  operations,  which  is  continually 
repeated,  that  most  commonly  employed  being  the  four- 
stroke  cycle,  in  which  the  working  fluid  passes  through 
a  complete  series  of  operations  in  four  strokes  of  the  piston, 
or  in  two  revolutions  of  the  crank  shaft.  It  is  obvious 
that  if  it  be  possible  to  complete  the  cycle  for  an  engine 
in  two  strokes  instead  of  four,  nearly  double  the  power 
might  be  obtained  from  the  same  size  of  cylinder,  and 
this  fact  has  led  to  the  introduction  and  wide  adoption  of 
gas  engines  working  on  a  two-stroke  cycle.  As  will  be  seen 
later,  the  two-stroke  cycle  Diesel  engine  has  already  made 
much  headway  and  must  of  necessity  be  adopted  for  large 
powers,  and  the  ultimate  general  employment  of  this  type 
for  the  propulsion  of  very  large  ships  no  longer  seems  in 
doubt.  In  the  two-stroke  cycle  engine,  one  stroke  in  two  is 
a  working  stroke,  as  against  one  in  four  with  the  four-stroke 
cycle,  and  a  still  further  advantage  may  be  gained  by  the 
employment  of  the  former  type,  and  using  also  the  double 
acting  principle  so  that  every  stroke  of  the  piston  is  a  working 
stroke.  The  possibilities  of  this  system  in  so  far  as  it  affects 
Diesel  engines  will  be  discussed  later  and  need  not  to  be 
further  entered  into  here, 

Thermo -Dynamic  Cycles. — The  principles  upon  wliich 
."11  heat  engines  theoretically  work,  may  be  divided  up  into 
three    main  divisions,  according  to  the  cycle  of  changes  of 


14      DIESEL  ENGINES  FOR  LAND  AND  MARINE  WORK 

state,  through  which  the  working  fluid  continually  passes, 
these  cycles  being  thermo-dynamic  cycles  in  contradistinc- 
tion to  the  mechanical  cycles  mentioned  in  the  last  para- 
graph. As  a  matter  of  fact  no  actual  engine  exactly  follows 
along  the  lines  of  the  theoretical  machine,  but  these  prin- 
ciples form  a  necessary  and  useful  basis  of  comparison. 
They  are  : — 

L  Constant  temperature  cycle. 

2.  Constant  volume  cycle. 

3.  Constant  pressure  cycle. 

In  engines  in  which  the  working  fluid  passes  through  one 
of  these  cycles,  there  is  a  certain  efiiciency  which  cannot 
be  exceeded  or  indeed  reached,  and  an  examination  of  the 
maximum  possible  efficiency  in  each  case  v,ill  lead  us  to  the 
points  of  difference  between  the  Diesel  and  other  heat 
motors. 

Constant  Temperature  Cycle. — In  this  cycle  all  the 
heat  is  taken  in  from  its  source  at  a  temperature  which 
remains  constant  during  the  whole  process,  and  the  heat 
is  rejected  also  at  a  constant  temperature  which  is  of  course 
lower  than  the  temperature  at  which  the  heat  is  received. 
All  cycles  can  be  illustrated  diagrammatic  ally  by  a  closed 
series  of  curves  drawn  relative  to  two  lines  at  right  angles, 
the  vertical  line  representing  the  pressure,  and  the  hori- 
zontal line  the  volume  of  the  gas  at  every  stage  of  com- 
pression and  expansion,  and  these  curves  are  the  indicator 
diagrams  of  perfect  engines  working  on  the  various  cycles. 
Fig.  3  represents  the  constant  temperature  cycle,  the  line 
OP  denoting  the  pressures,  and  OF  the  volumes  of  the  gas. 
be  represents  the  compression  line  in  which  the  gas  is  com- 
pressed adiabatically  from  the  point  b  where  the  volume  is 
V2,  the  pressure  Po,  and  the  temperature  Ti,  to  the  point  c, 
where  the  pressure  is  P3  the  volume  V3,  and  the  temi^erature 
T3.  Heat  is  taken  in  from  c  to  d,  at  constant  temperature 
T3,  the  pressure  and  volume  at  d,  being  P4  and  V4  respec- 
tively. From  d  to  a  is  adiabatic  expansion,  the  pressure, 
volume,    and    temperature    at    a,    being    Pi,  Vi,    and    Ti, 


GENERAL  THEORY  OF  HEAT  ENGINES 


15 


respectively.     From  a  to  b  heat  is  rejected  at  the  constant 
temperature  Ti,  this  completing  the  cycle. 

Tne  efficiency  of  an  engine  working  on  this  cycle  may  be 


V3 

Fig.   3 


•2         '4  r/ 

-Constant  Temperature  Cycle  Diagram. 


yi  V 


readily  expressed  in  terms  of  the  top  and  bottom  limits  of 
temperature  during  the  process.     If 

Q3  =  the  heat  taken  in  by  the  gas  and 
Qi  =  the  heat  rejected  at  the  lowest  temperature, 
then  Q3  —  Qi  =the  heat  usefully  employed  in  doing  work, 
and  the  efficiency  of  the  cycle  is  represented  by  the  ex- 
pression 

Q3  -  Qi 


n  = 


Q= 


As  generallj^  Q  =  tvkT,  where  w  is  the  weight  of  gas  and 
h  its  specific  heat  it  follows  that  since  neither  iv  nor  k  vary 


IG      DIESEL  ENGINES  FOR  LAND  AND  MARINE  WORK 

during  the  cycle  the  quantity  of  heat  is  always  directly 
proportional  to  the  absolute  temperature,  or  the  efficiency 
of  the  cycle  is 

This  expression  represents  the  efficiency  of  the  constant 
temperature  cycle,  T3  being  the  top  temperature  and  T^ 
the  bottom  temperature  during  the  complete  cj^cle. 

No  actual  engine  can  have  an  efficiency  so  high  as  the 
ideal  constant  temperature  engine,  and  an  ordinarily  effi- 
cient steam  engine,  working  between  limits  of  say  150  lb. 
per  sq.  inch  pressure  and  28  inches  vacuum,  or  say  819°  F. 
and  563°F.  absolute  temperatures,  would,  if  a  perfect  machine, 

have  an  efficiency =  31'3  per  cent.     As  a  matter 

■^         819 

of  fact  steam  engines  are  seldom  more  than  half  as  economi- 
cal as  the  ideal  constant  temperature  engine,  and  hence  an 
ordinary  steam  engine  would  have  an  actual  efficiency  of 
something  under  16  per  cent.,  and  this  may  be  compared 
with  the  possible  efficiencies  of  gas  and  Diesel  engines, 
deduced  later. 

Constant  Volume  Cycle. — An  engine  working  on  tlie 
constant  volume  cycle  differs  from  one  acting  on  the  con- 
stant temperature  cycle  in  that  all  the  heat  is  taken  in  while 
the  volume  of  the  gas  remains  constant,  and  the  heat  is 
rejected  under  similar  conditions.  The  cycle  is  shown  in 
Fig.  4  in  which  as  before  OP  represents  pressures  and  OV 
volumes.  Compression  takes  place  adiabatically  along  the 
hne  ah,  the  pressure,  volume,  and  temperature  changing 
from  Pi,  Vi,  and  Ti  at  a  to  Pa,  V2,  and  T2  at  h.  Heat  is 
then  taken  in  at  the  constant  volume  V2,  the  pressure  rising 
to  P3,  and  the  temperature  to  T3.  Next  there  is  adiabatic 
expansion  along  the  line  cd  till  the  volume  is  once  more  Vi, 
the  pressure  and  temperature  then  being  P3  and  T3  and 
finally  heat  is  rejected  while  the  volume  remains  unaltered 
until  the  original  pressure P]  and  temperature Ti  are  attained. 

To  obtain  the  thermal  efficiency  of  the  ideal  constant 


GENERAL  THEORY  OF  HEAT  ENGINES 


17 


volume  engine  let    Q2  =  the  heat  taken  in  by  the  fluid, 
j\nd  Q3  =  the  heat  rejected  by  the  fluid. 


' -— <3 


i^'iG.   4. — Constant  Volume  Cycle  Diagram. 

The  heat  usefully  employed  is  Q2  —  Q3  and  the  efficiency 


IS 


^2   —  Mg 

Q2 


or  1 


Q3 


Considering     1    lb.     of    gas    to 


eliminate  the  question  of  weight — this  remaining  constant 
throughout  the  cycle — the  quantity  of  heat  taken  in  or 
rejected  during  a  constant  volume  change  is,  generally, 
Q  =  A;„  (T„  —  Tj)  where  T^  and  T^  are  the  respective 
absolute  temperatures  before  and  after  the  change.     Hence 

Q,  =  h,  (T3  -  T2) 

Q3  =  K  (T4  -  TO 
from  which  it  follows  that  the  efficiency 

T4  -Ti 


w  =  1  - 


T, 


18  DIESEL  ENGINES  FOR  LAND  AND  MARINE  WORK 
From  formula  (4)  page  11,  with  adiabatic  expansion 

T4_  /Vsy-^  _T, 

since  the  vohime  Vi  is  constant  during  the  change  of  tem- 
perature from  T4  to  Ti  and  the  volume  V2  is  constant 
during  the  change  from  T2  to  T3 

hence  T\jzl}  =  !^  =  ^i 

T3  -  T,       T3       T, 

T 

that  is  n  =  I  * 


or  from  the  above         n  =  1 


©'" 


Vi 

The  ratio    —  is  usually  called  the  compression  ratio  and 

is  designated  by  r,  so  that  the  general  formula  for  the  effi- 
ciency of  the  constant  volume  cycle  is 

n=  1  -  —      1 

r  " 

Practically  all  gas  engines  work  on  a  cycle  closely  approxi- 
mating to  the  constant  volume  cycle. 

Constant  Pressure  Cycle. — In  this  cycle  all  the  heat 
is  taken  in  at  constant  pressure,  and  the  heat  is  also  rejected 
at  constant  pressure,  expansion  and  compression  of  the  gas 
being  adiabatic  as  before.  Fig.  5  represents  the  constant 
pressure  cycle  on  the  pressure-volume  basis. 

Starting  from  b  when  the  pressure,  volume  and  tempera- 
ture are  respectively  Pi,  V2,  and  T2,  the  gas  is  compressed 
adiabatically  to  c  where  P2  is  the  pressure,  V3  the  volume 
and  T3  the  temperature.  Heat  is  taken  in  along  the  line 
cd  at  constant  pressure  P2,  the  volume  at  d  being  V4,  and 
the  temperature  T4.  Adiabatic  expansion  next  occurs 
along  the  line  da,  to  a,  where  the  pressure,  volume,  and 
temperature  become  Pi,  Vi  and  Ti  respectively.  Heat  is 
then  rejected  at  constant  pressure  Pi,  along  the  line  ab  to 
the  starting  point  b  where  the  original  conditions  prevail. 


GENERAL  THEORY  OF  HEAT  ENGINES 


19 


As  before  let  Q2  =  heat  taken  in  by  the  fluid, 
and  Qi  =  heat  rejected  by  the  fluid. 

The  efficiency  of  the  cycle  is  then  n   =  — ~-i- 

and,  considering  1  lb  of  gas  Qo  =  kp  (T4  —  T3) 
and  Qi  =  k^  {T,  -  T,). 


The  efficiency  is  therefore  n  =  I 


T.  -  T, 


^3        y.    vz  V, 

Fig.   5. — Constant  Pressure  Cycle  Diagram. 

Expansion  along  da  and  compression  along  be  are  adiabatic 
80  that,  from  formula  (3)  page  11. 

T,  _Tt  -T, 
T. 


T= 


From  this 


T4  -T, 


Pi\5^^* 


T  /P  \ 

The  efl&ciency  is  thus  n  =  I  —    -i  =  l  — f— -M 

but  with  adiabatic  expansion  f — j    r      =  f— "j 


20      DIESEL  ENGINES  FOP.  LAND  AND  MARINE  WORK 

and  the  efficiency  may  be  expressed 

»  =  i-(vj       =1-7-' 

which  is  the  same  expression  as  was  obtained  for  the 
efficiency  of  the  constant  vokime  cycle,  and  in  fact  the 
efficiencies  of  the  constant  temperature,  constant  volume, 
and  constant  pressure  cycles  are  identical. 

It  is  at  once  apparent  from  the  above  results  that  what- 
ever cycle  of  operations  a  heat  engine  works  upon,  the  higher 
the  compression  ratio  can  be  made,  the  less  becomes  the 

fraction  —     ,  by  wliich  the   possible   efficiency  is  reduced 

below  unity,  and  hence  the  greater  becomes  the  efficiency 
of  the  engine  if  mechanical  and  other  losses  are  not  increased 
in  the  same  proportion.  It  is  for  this  reason  that  in  all  gas 
engines  it  is  desirable  to  work  with  a  high  compression 
ratio.  In  internal  combustion  engines  of  the  ordinary 
design,  that  is  to  say  gas  engines  working  on  the  constant 
volume  cycle,  the  compression  ratio  is  limited  by  the  fact 
that  during  the  suction  stroke  a  mixture  of  air  and  gas  is 
drawn  into  the  cylinder  and  the  mixture  is  compressed  in 
the  compression  stroke.  The  pressure  to  wliich  this  com- 
pression may  be  carried,  may  not  reach  beyond  a  relatively 
low  figure,  since  it  must  not  approach  the  temperature  of 
combustion  of  the  mixture,  for  were  it  to  reach  this  point, 
ignition  would  occur  before  the  commencement  of  the  working 
stroke,  i.e.  there  would  be  pre-ignition.  In  the  Diesel  engine 
pure  air  alone  is  dra\vii  into  the  cylinder  and  compressed, 
and  the  fuel  is  admitted  a\ter  compression,  so  that  very  much 
higher  compression  pressures  may  be  employed  than  with 
ordinary  gas  engines,  there  being  of  course  absolutely  no 
danger  of  pre-ignition.  In  actual  working  the  compression 
ratio  with  Diesel  engines  is  about  12,  as  against  6  or  7  with 
gas  engines,  which  shows  at  once  the  possibilities  of  higher 
efficiencies  with  Diesel  engines  than  with  the  usual  tj^pe  of 
internal  combustion  engines.  This  can  be  easily  illustrated 
by  working  out  the  thermal  efficiencies  in  the  two  cases 


GENERAL  THEORY   OF   MEAT  ENGINES 


21 


with  r  —  Q  and  r  =  12.  In  the  first  instance  n  =  -51 
while  in  the  second  n  =  -63,  showing  a  gain  of  over  23  per 
cent.  There  are  however  other  factors  influencing  the 
efficiency  of  the  actual  engines,  and  these  can  be  better 
ihustrated  by  an  examination  of  the  cycle  of  the  Diesel 
engine  as  constructed. 

Diesel  Engine  Cycle. — The  complete  cycle  of  operations 
of  the   Diesel  engine   will   be  fully  discussed  in  the  next 


: e 


Fig.   G. — Diesel  Cycle  Diagram. 

chapter,  but  for  present  purposes  it  is  sufficient  to  explain 
that  in  the  ordinary  four-stroke  engine  as  at  present  con- 
structed, the  cycle  of  operations  is  somewhat  similar  to 
constant  pressure  cycle,  except  that  the  rejection  of  heat 
to  the  exhaust  is  more  nearly  at  constant  volume  than  at 
constant  pressure,  and  that  the  expansion  and  compression 


22      DIESEL  ENGINES  FOR  LAND  AND  MARINE  WORK 

are  not  perfectly  adiabatic  which,  of  course,  is  impossible 
with  any  actual  heat  engine.  Fig.  6  represents  fairly  accur- 
ately the  Diesel  cycle  on  the  usual  pressure  volume  basis. 
Compression  takes  place  adiabatically  along  ah,  then  heat 
is  taken  in  at  constant  volume  to  the  point  c,  after  which 
there  is  adiabatic  expansion  to  d,  and  rejection  of  heat  to 
exhaust  at  constant  volume  to  a.  The  pressures  and  volumes 
at  the  various  stages  are  indicated  on  the  diagram,  while  the 
temperatures  correspond. 

Let  Q2  =  heat  taken  in  by  the  fluid, 
Qi  =  heat  rejected  to  exhaust, 

then  the  efficiencv  of  the  cycle  is  w  =  ^     ^",  or  1  —  —• 

Since  the  heat  is  taken  in  at  constant  pressure 

Q2=^^  (T3  -TO 
and  since  heat  is  rejected  at  constant  volume 
Q.  =  K     (T4  -  TO. 

PV 

From  the  general  formula  —  =  constant  we  have 

c  rp 

Mj=M?orT,=Tj'»     hence 
T,  T,  V, 

similarly  T4  =  T,  x  — '. 

From   the   general   formula    for   adiabatic   expansion    PV^ 

=  constant  it  follows  Pi  =  ^^-G/)^  '^"*^^  P4  ^  P2    (^\ 

and  hence  T,  =  T,  {^^  =  T,  (J^J 

Substituting  this  value  in  the  expression  for  Qi 


GENERAL  THEORY  OF  HEAT  ENGINES    23 

The  expression  — ?  is  the  ratio  of  the  cut-off  vohime  to  the 

V2 

clearance  volume  and  may  be  denoted  by  R.  The  efficiency 
of  the  Diesel  cycle  may  then  be  expressed  by  substituting 
in    the    formula 

n  =  1  —         wliich  then  becomes 


k„  Ti  (R^-  1) 

KT,  (R  -  1) 

Ti  R^  -  1 

=   1    -  ;;^    X 


n  =  1  - 


To      7(R  -  1) 

Since      the     compression     from     a      to     b     is     adiabatic 
T,         1 


To      r^ 


—  1 


as    before,    and    the    final    expression  for  the 


efficiency  of  the  Diesel  engine  is 


1  Rv  -  1 

n  =  I  — ,  X 


r^-i       7(R  -  1) 

From  this  it  would  be  seen  that  the  cut-off  ratio  exercises 
an  important  influence  on  the  thermal  efficiency  of  a  Diesel 
engine,  this  depending  on  the  two  variables,  the  compression 
ratio  and  the  cut-off  ratio. 

The  effect  of  the  alteration  of  the  cut-off  can  be  shown  by 
giving  actual  values  to  R  and  r.  Taking  the  clearance 
volume  as  yV  of  the  volume  swept  through  by  the  piston, 
and  the  cut-off  as  Vo  which  is  common  with  Diesel 
engines  and  referring  to  Fig.  6  we  have 


V3 

—  V2  =  —  and  V2  =  —  and  hence 
10         15 

Va 

Vs   Vs    .,    Vs 

—  —  =  —  or  V3  =  -  so  that 
15   10         0 

R  =  ^^  =  2.5 

Assuming  that  r  =  12  and  y  =  1-405  (which  is    somewhat 
higher  than  in  actual  engines)  the  thermal  efficiency  of  the 


24      DIESEL  ENGINES  FOR  LAND  AND  MARINE  WORK 

Diesel  cycle  from  the  formula  previously  deduced,  works 
out  at  -56,  whereas  with  the  same  values  of  r  and  7  but  with 
R  =  1-5  the  efficiency  becomes  '61. 

In  the  above  remarks  it  has  been  assumed  that  y  re- 
mains constant,  which  is,  of  course,  the  case  for  any  particu- 
lar mixture.  In  comparing  the  efficiencies  of  ordinary  gas 
engines  and  Diesel  engines  it  is  to  be  noted  however  that 
the  efficiency  on  any  cycle  becomes  larger  as  y  is  increased, 
which  occurs  when  the  gaseous  mixture  has  a  larger  propor- 
tion of  air,  or  as  it  is  generally  termed,  is  a  leaner  mixture. 
In  Diesel  engines  the  mixture  is  very  much  leaner  than  in 
gas  engines,  and  hence  this  accounts  to  a  certain  extent  for 
the  greater  economy  of  this  type  of  engine. 

Reasons  for  the  High  Efficiency  of  the  Diesel  Engine. 
— Summarizing  the  foregoing  analysis  it  may  briefly  be 
said  that  the  superior  efficiency  of  the  Diesel  engine  is  due 
to  several  causes,  the  first  being  the  successful  employment 
of  high  compression  pressures  rendered  possible  by  the  fact 
that  air  alone  is  compressed  in  the  cylinder  and  not  a  mixture 
of  fuel  and  air  in  which  the  temperature  of  ignition  always 
limits  the  compression  pressure.  In  the  second  place,  a 
leaner  mixture  may  be  employed  than  with  gas  engines,  less 
weight  of  fuel  is  necessary,  and  the  loss  in  the  cooling  water 
is  correspondingly  reduced.  There  are,  moreover,  fvu'ther 
reasons  which  probably  exercise  an  important  influence, 
namely,  the  perfect  combustion  of  the  fuel  due  to  the  high 
pressure  during  the  whole  combustion  period  and  mechanical 
advantages  such  as  the  efficient  method  of  its  injection.  It 
is  obvious  that  oil  with  a  high  flash  point  is  very  suitable 
for  the  Diesel  engine,  thus  permitting  of  the  cheapest  crude 
residue  oils  being  employed.  On  the  other  hand,  a  separate 
compressor  is  necessary  to  inject  fuel  with  compressed  air 
at  a  higher  pressure  than  the  compressed  air  in  the  cylinder, 
and  this  causes  a  slight  loss  of  efficiency,  usually  about  6  per 
cent.,  which  is,  however,  of  no  great  import. 

It  must  be  distinctly  remembered  that  the  Diesel  engine 
cycle  itself  does  not  account  for  the  economy  of  the  engine 
since,  as  a  matter  of  fact,  the  constant  pressure  cycle  is 


GENERAL  THEORY  OF  HEAT  ENGINES    25 

rather  less  cificient  than  that  at  constant  vohime,  on  which 
most  gas  engines  work,  provided  the  conditions  are  the 
same.  In  other  words,  for  the  same  compression  pres- 
sure the  constant  volume  engine  would  be  superior  to  the 
constant  pressure  engine,  but  for  the  reasons  already  given 
it  is  impossible  that  a  gas  engine  should  approach  the  con- 
ditions which  are  easily  attained  with  the  Diesel  engine. 
The  limits  of  pressure  of  the  working  fluid  are  fixed  by  the 
ultimate  strengths  of  the  materials  of  which  the  engine  parts 
are  constructed,  and  the  Diesel  cycle  gives  the  maximum 
economy  for  these  limits  of  pressure. 

Thougli  very  much  higher  compression  pressures  (but  not 
maximum  pressures)  are  employed  in  the  Diesel  engine  than 
in  gas  engines,  the  temperature  at  the  end  of  combustion  in 
the  first  case  is  very  considerably  below^  that  in  the  second, 
since  the  period  during  which  the  burning  of  the  fuel  occurs 
is  so  long  compared  with  the  explosion  in  the  gas  engine 
cylinder,  thus  allowing  the  heat  to  be  taken  up  to  a  greater 
extent  by  the  jacket  water.  The  combustion  in  the  Diesel 
engine  is  however  by  no  means  isothermal,  and  the  tempera- 
ture rises  a  good  deal  after  the  injection  of  the  fuel  and  also 
to  a  slight  extent  after  the  fuel  valve  is  closed,  but  allowing 
for  this  the  important  fact  remains  that  in  Diesel  engines, 
in  spite  of  high  pressures,  the  temperatures  are  less. 

The  following  table  gives  the  actual  consumption  in  British 
Thermal  Units  per  B.H.P.  hour  for  various  types  of  engines, 
namely,  non-condensing  and  condensing  steam  engines,  tur- 
bines using  superheated  steam,  suction  gas  engines,  and  Diesel 
engines.  The  figures  quoted  represent  generally  the  limit- 
ing results  obtained  in  practice,  and  the  efficiencies  are  also 
given  based  on  the  heat  equivalent  of  one  H.P.  hour  which 

.       33000    X    GO  o;.<-    T^rpi     TT         rru  J- 

IS =  254o  B.ih.U.     Ihe  correspondmg  ranges 

778 

of  pressure  are  also  added. 


26      DIESEL  ENGINES  FOR  LAND  AND  MARINE  WORK 


Type  of  Engine. 


Non-condensing  steam  en- 
gines     

Condensing  steam  engines 
and  turbines  using  super- 
heated steam. 

Suction  gas  engines 

Diesel  engines    .... 


Range  of 

Pressure 

lbs.  per  sq. 

inch. 


160  to  220 
300  to  370 
500  to  600 


B.Th.U.  per 
B.H.P.  Hour. 


30,000  to  38,000 

17,000  to  25,000 

11,000  to  14,000 

7,500  to  8,000 


Efficiency 
per  cent. 


8-4  to  6-6 

15  to  10 
23  to  18 
34  to  32 


Two-cycle  Diesel  engines  are  about  2  per  cent,  less  efficient 
than  the  four-cycle  slow  speed  type,  and  all  the  efficiencies 
refer  to  the  engines  running  under  full  load  condition  being 
of  course  lower  with  smaller  outputs. 

These  figures  are  all  the  effective  efficiencies,  but  the  thermal 
efficiencies  are  very  much  higher — ^the  efficiency  for  Diesel 
engines  being,  for  instance,  from  42  to  48  per  cent. 

Practical  Diesel  Engine  Cards. — Needless  to  say,  the 
actual  indicator  cards  obtained  from  Diesel  engines  in  prac- 
tice are  by  no  means  identical  with  the  ideal  diagram  given 
on  page  21.  At  the  same  time  by  very  careful  adjustment 
of  the  engine,  it  is  possible  to  obtain  a  very  good  card  show- 
ing quite  a  prolonged  combustion  at  constant  pressure, 
althovigh  this  is  usually  only  possible  at  full  load.  The 
maximum  pressure  attained  after  the  compression  stroke 
is  generally  between  450  and  500  lb.  per  sq.  inch,  470  lb. 
per  sq.  inch  being  an  ordinary  figure.  In  two-cycle  motors 
it  is  frequently  less  than  this,  although  in  some  cases  it  is 
exceeded,  particularly  for  instance  in  a  Junkers  motor,  for 
reasons  which  will  be  understood  from  the  description  of 
this  engine  later.  Considerable  improvement  may  some- 
times be  effected  in  the  card  by  an  alteration  of  the  lift  of 
the  fuel  valve.     In  general  this  is  between  three  and  four 


GENERAL  THEORY  OF  HEAT  ENGINES 


27 


mm.,  although  the  actual  lift  clue  to  the  knocker  of  the 
cam  may  be  considerably  in  excess  of  this  in  order  to  allow 
a  reasonable  clearance  between  the  knocker  and  the  roller 
of  the  fuel  valve  lever.  The  amount  of  clearance  to  be 
allowed  depends  upon  the  accuracy  with  which  the  motor 
has  been  designed,  and  the  experience  gained  in  operation, 
and  in  some  cases  it  is  as  much  as  3  to  4  mm.,  and  in  others 
not  much  greater  than  |  mm. 

The  following  table  gives  the  actual  setting  of  the  valves 
of  one  of  the  cylinders  in  an  engine  of  the  four-cycle  type 
running  at  300  r.p.m.  developing  300  B.H.P.  and  having 
four  cylinders.  The  dimensions  of  the  cylinders  were 
380  mm.  bore  and  420  mm.  stroke. 


Fuel  valve  opens  per  cent,  before  upper  dead  centre    . 

Lift  fuel  mm 

Fuel  valve  closes  per  cent,  after  upper  dead  centre    . 
Starting  valve  opens  per  cent,  after  upper  dead  centre 

Stroke  of  starting  valve  mm 

Starting  valve  closes  per  cent,  after  upper  dead  centre 

Play  between  roller  and  cam  (s.v.  closed)  mm. 

Air  suction  valve  opens  per  cent,  after  upper  dead  centre 

Stroke  of  air  suction  valve  mm 

Air  suction  valve  closes  per  cent,  after  upper  dead  centre 
Play  between  roller  and  cam  (air  suction  v.  closed)  mm. 
Exhaust  valve  opens  per  cent,  before  lower  dead  centre   . 

Stroke  of  exhavist  valve  min 

Exhaust  valve  closes  per  cent,  after  upper  dead  centre 
Play  between  roller  and  cam  (e.v.  closed)  mm. 

Fuel  nozzle,  bore  of  flame  disc  mm 

Diameter  of  holes  in  atomiser  plates  mm 

Distance  apart  of  holes  in  atomiser  plates 

Diameter  of  fuel  test  valve  mm. 

Compression  space  in  working  cylinder  mm 

Liner  to  be  placed  in  connecting  rod  at  top  end 


0-7 

31 

8 

2 

5 
38 

0-2 

6 
30 

8 

0-2 
25 
29-8 

3 

0-4 

4-2 

2 

3 

11 
21-3 

2-5 


In  a  two-cycle  marine  engine  of  the  Sulzer  type  Mith 
port  scavenging  having  four  cylinders  310  mm.  bore  and 


28   DIESEL  ENGINES  FOR  LAND  AND  MARINE  WORK 

with  450  mm.  stroke,  running  at  280  r.p.m.,  the  following 
were  the  lifts  of  the  fuel  valve  : — 


Lifts 

OF  Fuel  Value  for  Two-Cycle 

380  H.P.  Motor. 

Minimum  Lift. 

ZMaximtii  Lift. 

Angle 

of 
Lead. 

Angle 
open 
after 
dead 

centre. 

Per 
cent, 
stroke 
dura- 
tion. 

Lift 

of 

Valve. 

mm. 

Angle 

of 
Lead. 

Angle 
open 
after 
dead, 
centre. 

Per 

cent, 
stroke 
dura- 
tion. 

Lift 

of 

Valve. 

mm. 

Ahead    . 
Astern    , 

3°  38' 

4°  18' 

23°  30' 
24°  44' 

4-94 
5-46 

1-5 
1-75 

10°  13' 
10°     5' 

43°  41' 
43°  13' 

16-24 
15-94 

5 
5 

In  the  descriptions  of  various  Diesel  engines  given  later, 
it  is  explained  that  in  some  types  a  fuel  pump  is  provided 
for  each  cyhnder,  whereas  in  other  engines  there  is  only  one 
fuel  pump  for  perhaps  four  or  six  cylinders.  In  stationary 
engine  practice,  it  is  still  more  common  to  use  only  one  pump 
and  supjjly  the  fuel  to  a  distributing  box  from  which  pipes 
are  taken  to  the  various  fuel  valves  of  the  cyhnders,  but  for 
marine  work,  especially  for  two-cycle  engines,  most  builders 
prefer  to  employ  one  fuel  pump  for  each  cylinder.  In  cases, 
however,  where  one  fuel  pump  has  to  supply  a  number  of 
cylinders  it  is  especially  important  to  ascertain  by  means 
of  indicator  cards  that  all  the  cj^linders  are  doing  approxi- 
mately the  same  amount  of  work,  otherwise  it  is  easy  for 
one  to  become  much  overloaded,  even  though  the  whole 
engine  itself  is  only  developing  the  normal  output.  The 
set  of  cards  given  in  Fig.  9  are  taken  simultaneously  upon 
a  six-cylinder  four-cycle  engine  of  1,500  I. H.P. ,  and  in  this 
case  one  fuel  pump  supplies  all  the  cylinders.  It  will  be 
seen  that  even  though  the  variation  is  not  great  it  is  quite 
well  marked. 


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CHAPTER    II 
ACTION  AND  WORKING  OF  THE  DIESEL  ENGINE 

FOUR-CYCLE  ENGINE  —  TWO-CYCLE  ENGINE — TWO-CYCLE 
DOUBLE  ACTING  ENGINE — HORIZONTAL  ENGINE — HIGH 
SPEED  VERTICAL  ENGINE — RELATIVE  ADVANTAGES  OF 
THE    VARIOUS    TYPES    OF    ENGINE — LIMITING     POWER    OF 

DIESEL    ENGINES WEIGHTS    OF   DIESEL    ENGINES FUEL 

FOR  DIESEL   ENGINES. 

The  essential  difference  between  the  Diesel  engine  and 
practically  all  other  motors  working  with  gaseous  or  liquid 
fuel,  is  that  it  is  in  reality  an  internal  combustion  engine  in 
contradistinction  to  other  gas  and  oil  engines  which  are, 
strictly  speaking,  internal  explosion  engines. 

Four-stroke  Cycle  Engine. — In  four-stroke  cycle  gas 
engines  of  the  ordinary  explosion  type  a  mixture  of  gas  and 
air  is  drawn  into  the  cylinder  during  the  suction  stroke,  and 
compressed  in  the  following  stroke,  the  mixed  gases  being 
then  exploded  by  external  means  (i.e.  by  ignition)  in  the 
third  stroke,  which  is  the  working  stroke  of  the  cycle.  The 
method  of  operation  of  the  Diesel  engine  as  has  been  par- 
tially explained  in  the  last  chapter,  is  on  quite  a  different 
principle,  and  is  as  follows  for  a  motor  working  on  the  four- 
stroke  cycle,  considering  a  vertical  engine  of  the  usual 
type:— 

1.  In  the  first  downward  stroke  of  the  piston  air  is  sucked 
into  the  engine  cylinder  direct  from  the  atmosphere  through 
a  slotted  cylinder,  and  thence  through  the  main  air  inlet 
valve  on  the  top  of  the  cyUnder.  At  the  end  of  the  stroke 
the  cylinder  is  full  of  pure  air  at  practically  atmospheric 
pressure,  ready  for  the  compression  stroke. 


ACTION  AND  WORKING  OF  THE  DIESEL  ENGINE     33 

2.  In  the  next  stroke  the  air  is  compressed  to  the  required 
pressure,  usually  about  500  lb.  per  sq.  inch,  while  the  tem- 
perature rises  to  between  1,000°  F.  and  1,100°  F.,  all  the 
valves  of  course  being  closed  during  this  action.  In  this 
compression  period  a  certain  amount  of  negative  work  has 
to  be  done,  detracting  somewhat  from  the  efficiency  of 
the  cycle,  but  as  the  compression  is  very  approximately 
adiabatic,  nearly  all  the  work  is  returned. 

3.  During  the  early  portion  of  the  third  and  working 
stroke  the  fuel  oil  is  injected  into  the  cylinder  above  the 
piston  by  a  blast  of  air  at  a  higher  pressure  than  that  in  the 
cylinder  (about  800  lb.  per  sq.  inch)  tlirough  a  special  form 
of  needle  valve.  Combustion  takes  place  during  this  period 
as  the  temperature  of  the  compressed  air  in  the  cylinder  is 
above  the  burning  point  of  the  oil  fuel.  The  duration  of  this 
part  of  the  stroke  depends  on  the  setting  of  the  valves,  but 
cut-off  usuaU}^  occurs  not  later  than  one-tenth  of  the 
stroke  at  full  load.  After  cut-off  when  the  fuel  inlet  valve 
closes,  combustion  continues  for  a  short  period,  expansion 
then  occurs  and  work  is  done  on  the  piston  for  the  rest  of  the 
stroke.  Just  before  the  piston  reaches  the  end  of  its  travel 
the  exhaust  valve  begins  to  open,  and  the  pressure  drops  off 
rapidly,  since  it  is  obvious  that  to  carry  expansion  to  any- 
thing like  its  full  extent  would  necessitate  inordinately  large 
cylinders. 

4.  In  the  final  stroke  the  exhaust  valve  remains  open 
and  the  burnt  gases  are  expelled  from  the  cylinder  into  the 
exhaust  pipe,  and  the  cycle  of  operations  begins  once  more, 
the  cylinder  being  ready  to  receive  a  further  charge  of  air  on 
the  next  out  stroke  of  the  piston. 

Fig. 10  shows  an  indicator  card  of  an  actual  Diesel  engine, 

ah  representing  the  first  or  suction  stroke  in  which  the  air  is 

drawn  in,  be  the  compression  of  the  air  more  or  less  adiabatic- 

ally,  cd  the  combustion  of  the  fuel  during  the  admission 

portion  of  the  next  stroke,  and  de  the  following  expansion 

of  the  mixture  until  the  exhaust   valve  opens  at  e  when 

for  the  remainder  of  the  stroke  ef,  the  pressure  falls  more 

rapidly  as  some  of  the  gases  are  expelled  ;   fa  represents  the 

D 


34   DIESEL  ENGINES  FOR  LAND  AND  MARINE  WORK 

final  stroke  in  which  all  the  products  of  combustion  are 
exhausted  through  the  exhaust  valve. 

Diesel's  original  proposal  was  to  build  an  engine  working 
practically  on  the  constant  temperature  cycle,  and  though 
the  engines  as  now  made  work  in  a  manner  somewhat  differ- 
ent from  that  which  the  inventor  first  intended,  the  reprint 


c    d 


Fig.  10. 


Diagram  showing  action  of  Diesel  Engine. 


of  the  patent  specification  in  the  Appendix  of  this  volume 
will  prove  interesting  both  as  an  historical  document,  and 
as  indicating  the  objects  which  Diesel  had  in  view  with  his 
earliest  engines. 

As  has  been  seen  by  the  diagram  and  description  of  the 
action  of  actual  Diesel  engines,  the  combustion  Hne  of  the 


ACTION  AND  WORKING  OF  THE  DIESEL   ENGINE    35 

cycle,  which  was  originally  intended  to  be  isothermal,  is, 
in  reality,  a  constant  pressure  line  and,  as  a  matter  of  fact, 
by  no  means  an  isothermal,  as  the  temperature  rises  to  a 
considerable  extent  during  the  burning  of  the  fuel,  and  pro- 
bably for  a  short  period  after  cut  off.  This  type  of  com- 
bustion was  also  intended  and  reaUzed  by  Diesel  and  is 
described  in  his  second  patent. 

It  is  very  important,  however,  to  note  from  a  practical 
point  of  view,  that  the  duration  of  the  combustion  is  con- 
siderable, and  hence  there  is  much  greater  time  to  get  rid  of 
the  heat  by  the  jacket  water  than  in  gas  engines,  where  the 
explosion  is  instantaneous  and  the  temperature  must  of 
necessity  rise  very  rapidly.  It  follows,  therefore,  that  for 
the  same  ynaximum  pressures  in  the  cylinders  of  a  gas  engine 
and  a  Diesel  engine  the  temperature  rise  in  the  first  case 
would  be  much  higher  than  in  the  latter,  and  it  is  to  be 
remembered  that  these  maximum  pressures  are  not  very 
different,  but  tliat  in  the  gas  engme  the  highest  point  is  not 
reached  during  compression,  but  only  after  ignition  of  the 
mixture.  Since  a  Diesel  engine  may  work  with  much  higher 
compression  pressures  than  a  gas  engine,  and  yet  not  be 
subjected  to  such  high  temperatures,  this  points  to  the  fact 
already  well  estabhshed  that  greater  powers  may  be  ob- 
tained per  cyUnder  than  with  the  ordinary  types  of  internal 
combustion  engines,  though  there  are,  however,  other  factors 
governing  this  matter. 

It  is  obvious  from  the  description  previously  given  that 
the  Diesel  engine  is  not  a  self -starting  motor  any  more  than 
other  internal  combustion  engines,  and  the  invariable  method 
of  running  up  the  machine  is  by  the  employment  of  com- 
pressed air  which  is  admitted  to  the  cjdinder  through  a 
separate  starting  valve  in  the  cylinder  cover,  arranged  so 
that  it  cannot  be  in  operation  at  the  same  time  as  the  fuel 
inlet  valve.  The  engine  is  barred  round  until  the  crank  is 
well  over  the  dead  centre  and  it  runs  as  an  air  engine  until 
it  has  attained  sufficient  speed  to  take  up  its  work  as  an  oil 
engine,  which  it  does  after  two  or  three  revolutions.  A 
supply  of  compressed  air  is  therefore  necessary  both  for 


36   DIESEL  ENGINES  FOR  LAND  AND  MARINE  WORK 

starting  the  engine,  and  for  the  blast  for  fuel  injection  into 
the  cylinder  when  the  engine  is  running.  The  usual  arrang(v 
ment  is  to  provide  three  cylindrical  air  reservoirs  of  quite 
small  dimensions,  two  for  starling  (one  as  a  standby)  and 
one  for  injection  blast,  and  the  supply  is  maintained  by  an 
air  compressor  driven  off  the  engine  itself,  of  such  capacity 
as  to  easily  deUver  all  the  air  needed  at  the  required  pressure. 
All  the  valves  are  arranged  in  the  cylinder  cover  with  the 
vertical  type  engine  which  has  hitherto  been  almost  univer- 
sal, although  the  horizontal  type  is  now  being  manufactured 
by  some  firms  on  a  large  scale.  There  are  thus  in  a  single 
cylinder  four-cycle  engine  four  valves,  the  fuel  inlet,  the  air 
inlet,  the  exhaust,  and  the  starting  valves.  Each  of  these 
is  operated  separately  by  a  lever  whose  motion  is  obtained 
from  a  cam  on  a  cam  shaft,  which  is  driven  through  spur 
gearing  and  a  vertical  shaft,  from  the  crank  shaft.  All  the 
valves  are  kept  on  their  seats  by  strong  springs.  It  is  evi- 
dent that  by  a  simple  adjustment  of  any  of  the  cams,  the 
valves  can  readily  be  set  to  suit  the  requirements  of  the 
engine,  and,  of  course,  in  a  multi-cjdinder  engine,  but  one 
starting  valve  is  essential  (though  more  are  sometimes  fitted) 
since  the  motor  is  run  up  on  one  cylinder,  and  the  remaining 
cylinders  are  then  only  provided  with  fuel  inlet,  air  inlet, 
and  exhaust  valves.  Fig.  11,  an  indicator  card  of  a  250 
B.H.P.  engine,  shows  how  readily  any  defect  in  the  adjust- 
ment of  the  valves  can  be  seen,  as  it  is  evident  from  this  card 
that  ignition  occurs  too  late  due  to  the  fuel  inlet  valve  not 
opening  early  enough.  Fig. I2[s  an  indicator  card  taken  on 
the  same  cylinder  after  adjust mg  the  valve,  which  shows  by 
the  horizontal  combustion  line  at  top  pressure  that  the  fuel 
is  admitted  at  the  right  moment. 

The  air  compressor  is  arranged  in  different  ways  by  various 
makers  of  Diesel  engines,  some  preferring  to  drive  it  by  a 
link  off  the  connecting  rod,  while  others  have  the  piston  or 
pistons  of  the  compressor  driven  by  eccentrics  on  the  shaft. 
Usually  two  or  three  stage  compressors  are  emplo^^^ed,  parti- 
cularly with  large  engines,  and  in  marine  installations,  a 
separate   auxiliary  air  compressor  driven  by  a  Diesel  engine 


ACTION  AND  WORKING  OF  THE  DIESEL  ENGINE     3? 

or  other  motor  is  absolutely  essential.  The  regulat  ion  of  the 
engine  is  effected  in  many  wa3's,  but  tlie  general  principle 
usually  consists  in  simply  regulating  the  amount  of  oil 
admitted  to  the  cj^Kncler  v'.a,  a  small  feed  pump  actuated 
from  eccentrics  on  the  governor  shaft.  This  method  is 
obviously  more  efficient  than  that  most  usually  adopted  in 
gas  engines  where  the  hit  and  miss  principle  is  employed, 
though,  of  course,  many  other  efficacious  methods  are  now 
used  in  the  more  modern  engines. 

Full  details  of  the  construction  of  various  types  of  Diesel 
engines  will  be  given  in  the  next  chapter,  and  need  not  be 
further  discussed  here. 

Two -Cycle  Engine. — For  many  years  after  its  inception 
the  Diesel  engine  was  constructed  solely  of  the  four-cj-cle 
single  acting  type,  but  of  late  much  progress  has  been  made 
in  the  manufacture  of  an  engine  working  on  the  two-stroke 
cycle.     The  general  action  of  such  an  engine  is  as  follows  : — 

1.  Consider  the  piston  at  the  end  of  its  stroke  in  its  bottom 
position.  The  cylinder  is  full  of  air  at  nearly  atmospheric 
pressure,  and  this  is  compressed  during  the  first  or  upward 
stroke  of  the  cycle  to  the  usual  top  compression  pressure  of 
500  lb.  per  sq.  inch,  as  in  the  second  stroke  of  the  four- 
stroke  cycle. 

2.  During  the  second  stroke,  combustion,  expansion,  ex- 
pulsion of  the  burnt  gases  to  the  exhaust  and  the  filling  of 
the  cylinder  with  fresh  air  are  the  operations  which  have  to 
be  effected.  Fuel  is  sprayed  into  the  cyUnder  during  the 
early  portion  of  the  stroke,  through  the  inlet  valve,  by  com- 
pressed air  as  before.  This  valve  then  closes  and  expansion 
occurs  while  the  piston  passes  through  about  another  75 
per  cent,  of  its  stroke,  at  which  point  the  exhaust  opens  and 
the  products  of  combustion  begin  to  pass  out.  Air  vinder  a 
pressure  of  about  4  to  8  lb.  per  sq.  inch  then  enters  the  cyHn- 
d(r  through  a  separate  valve  or  port  in  the  cylinder,  being 
e.upplied  from  a  so-called  scavenge  pump,  which  is  quite 
separate  from  the  air  compressor  for  the  provision  of  fuel 
ignition  and  starting  air  supply,  the  necessity  of  which  is 
apparent.     All  the  exhaust  gases  are  thus  forced  out  through 


38   DIESEL  ENGINES  FOR  LAND  AND  MARINE  WORK 

the  exhaust  ports,  and  at  the  end  of  the  stroke  the  cylinder 
is  left  full  of  pure  air  with  all  the  valves  closed,  ready  for 
the  first  stroke  of  the  next  cycle. 

The  diagram  for  this  cycle  does  not  differ  mr/icrially  from 
that  for  the  four-stroke  cycle  as  is  seen  in  Fig.  13,  which 
illustrates  the  two-stroke  cycle,  cd  represents  the  combus- 
tion of  fuel,  de  the  expansion  until  e,  when  the  exhaust 
ports  begin  to  open,  the  rapid  fall  of  pressure  to/,  along  ef, 
being  notable,  and  during  the  process  of  exhaust  the  cylinder 


Fig.  13. — Two  stroke  Cycla  Dia;5rarQ. 

is  filled  with  air  from  the  scavenge  pump.  There  is  no  longer 
a  horizontal  line  representing  the  entrance  of  the  air  at 
atmospheric  pressure  as  in  the  four-&troke  diagram,  since  all 
the  air  is  admitted  at  a  pressure  above  atmospheric.  The 
admission  of  air  continues  along  fg  to  the  predetermined 
point  g,  after  which  compression  takes  place.  The  scavenge 
valve  or  port  opens  slightly  after  the  exhaust  port,  so  that 
the  pressure  has  already  dropped  to  some  extent  before  the 
admission  of  the  scavenge  air. 

As   far  as  constructional  details  go,  the  two-stroke  cycle 


ACTION  AND  WORKING  OF  THE  DIESEL  ENGINE     39 

engine  differs  from  the  four-stroke  type  in  the  arrange- 
ment of  valves,  and  the  provision  of  a  scavenge  pump  in  the 
former  case.  Otherwise  the  engines  are  identical.  In  largo 
engines  this  pump  is  usually  placed  in  line  with  the  engine 
cyhnders,  and  its  piston  driven  through  a  connecting  rod 
off  an  extension  of  the  crank  shaft,  while  in  other  cases  it  is 
worked  by  levers  off  the  connecting  rod. 

The  scavenge  pumps  are  designed  to  deliver  air  at  a 
pressure  of  4  to  8  lb.  per  sq.  inch,  but  this  depends  to  a  large 
extent  on  the  size  and  type  of  the  scavenge  valves.  There 
is  no  atmospheric  air  inlet  valve,  and  the  scavenge  air  may 
be  admitted  either  through  valves  in  the  cover  of  the  cjdin- 
der  or  through  ports  near  the  bottom  of  the  cyhnder.  The 
exhaust  ports  are  in  any  case  arranged  vertically,  extending 
in  the  cylinder  walls  from  the  bottom  of  the  piston  stroke, 
a  distance  of  about  15  per  cent,  of  the  stroke. 

Two -Cycle  Double  Acting  Engine. — In  this  cycle,  each 
stroke  is  a  working  stroke,  and  the  action  may  be  understood 
by  considering  each  cylinder  as  two  separate  cylinders  with 
the  same  central  exhaust  ports  serving  for  each  cylinder, 
and  separate  inlet  valves  at  the  top  and  bottom.  The 
cylinder  has  of  necessity  to  be  considerably  longer  than  with 
the  single  acting  type,  and  the  piston  is  rather  less  than  half 
its  length.     The  action  is  as  follows  : — 

Consider  the  piston  in  its  bottom  position  when  it  is  fully 
uncovering  the  exhaust  valves  in  the  centre,  and  the  space 
above  the  piston  is  full  of  pure  air  which  has  been  injected 
by  the  scavenge  pump,  while  below  the  piston  in  the  cylin- 
der is  the  air  which  has  been  compressed  to  a  high  pressure 
in  the  last  downward  stroke.  The  upward  stroke  is  then  a 
combination  of  the  two  strokes  in  the  two-cycle  single 
acting  engine  already  described.  Above  the  piston,  the  air 
is  compressed,  while  below  the  piston  there  is  first  fuel  injec- 
tion and  combustion,  then  expansion,  and  finally  opening 
of  the  scavenge  valves,  admission  of  scavenge  air  and  the  con- 
sequent expulsion  of  the  burnt  gases  to  the  exhaust  through 
the  exhaust  ports  which  are  uncovered  as  before,  as  the 
piston  reaches  the  end  of  its  stroke. 


40   DIESEL  ENGINES  FOR  LAND  AND  MARINE  WORK 

Horizontal  Engine. — Although  Diesel  himself  built  a 
horizontal  type  of  engine  in  the  early  days  of  development, 
up  to  within  a  j'ear  or  two  ago  all  Diesel  engines  were  con- 
structed for  commercial  purposes  of  the  vertical  tj^e.  Re- 
cently, however,  an  engine  of  the  horizontal  type  has  been 
perfected,  which  may  possess  advantages  in  certain  cases, 
where,  for  instance,  the  available  head  room  is  limited  and 
floor  space  is  of  secondary  importance,  since  the  horizontal 
machine  is  much  lower,  but  occupies  a  greater  superficial 
area  than  the  vertical  type.  This  engine  is  made  both  single 
and  double  acting,  and  differs  in  no  essential  details  from 
the  vertical  engine  as  far  as  its  general  method  of  working 
is  concerned.  The  fuel  inlet  valve  is  arranged  horizontally 
on  the  end  of  the  cylinder,  while  the  air  inlet,  and  the  ex- 
haust or  scavenge  valves  as  the  case  may  be,  are  fitted  on  the 
top  side  or  bottom  of  the  cylinder,  all  being  actuated  by 
rolUng  levers,  operated  by  cams  or  eccentrics  on  a  horizontal 
shaft  somewhat  as  in  the  usual  type  of  horizontal  gas 
engine,  the  shaft  being  driven  through  gearing  from  the 
crank  shaft.  The  compressor  is  ordinarily  coupled  to  the 
crank  shaft  direct,  and  may  be  of  the  two  or  three  stage  type 
— generally  the  former.  This  engine  possesses  the  advan- 
tage of  easy  accessibility  of  all  the  parts  for  cleaning  and 
repair,  less  pressure  on  the  bedplate  and  foundations,  and 
has  a  rather  lower  initial  cost  than  a  vertical  engine. 

High  Speed  Vertical  Engines. — For  land  work,  which 
comprises  chiefly  dynamo  driving  for  electrical  work,  a  high 
speed  engine  possesses  advantages  over  a  low  speed  one, 
inasmuch  as  it  reduces  the  size,  cost,  and  weight  of  the 
dynamo,  while  its  own  size  and  weight  a,re  also  minimized. 
The  usual  speed  of  the  ordinary  vertical  four-cycle  slow  speed 
Diesel  engine  varies  from  about  150  to  250  revolutions  per 
minute  according  to  the  power,  but  the  high  speed  type, 
which  is  now  built  by  a  large  number  of  firms,  runs  at  speeds 
ranging  from  180  to  350  revolutions  per  minute,  or  more. 
The  principle  of  this  maclJne  is  precisely  the  same  as  the 
slow  speed  type,  but  all  parts  are  usually  enclosed,  and  forced 
lubrication,  with  a  pressure  of  50  to  70  lb.  per  sq.  inch,  is 


ACTION  AND  WORKING  OF  THE  DIESEL  ENGINE     41 

adopted.  The  crank  chamber  is  entirely  sealed  up,  and  has 
inspeclion  doors,  as  in  a  st  am  engine  of  the  high  speed 
vertical  type,  while  the  cam  shaft  and  cams  generally  run  in 
an  enclosed  oil  bath.  The  advantages  claimed  for  the  high 
speed  engine,  are,  beyond  any  saving  in  connexion  with  its 
drive,  the  reduced  space  and  weight,  the  lesser  height,  and 
a  reduction  in  capital  cost. 

Relative  Advantages  of  the  Various  Types  of  Engine. 
— Engineering  design  and  construction  is  invariably  a 
matter  of  compromise,  and  it  is  difficult  or  impossible  to  lay 
down  general  laws  to  be  always  followed,  since  in  many 
individual  cases,  there  are  considerations  which  modify 
what  might  in  the  ordinary  way  be  thought  the  most  suit- 
able and  efficient  arrangement.  The  following  remarks 
regarding  the  applications  of  the  several  types  of  engines 
should  therefore  only  be  taken  as  applj'ing  in  such  in- 
stances where  no  special  considerations  are  likely  to  render 
departures  from  the  usual  practice  advisable  or  necessary. 

The  largest  experience  has  been  gained  in  Diesel  engines 
of  the  slow  speed,  four-stroke  type,  and  their  efficiency  must 
inevitably  be  slightly  higher  than  that  of  any  other,  whilst 
the  absolute  reliability  and  low  running  cost  have  been 
abundantly  proved  during  the  last  fifteen  j'ears.  These 
facts  alone  will  for  a  long  time  render  the  application  of 
this  type  most  general,  and  for  engines  of  small  and  moderate 
powers  it  is  difficult  to  see  the  reasons  which  would  render  it 
advisable  to  displace  them  for  stationary  work,  except  in 
cases  where  the  space  or  height  available  is  very  limited. 
The  tendency  of  late  years  is  to  employ  larger  engines,  a 
tendency  which  will  probably  be  more  accentuated  in  the 
future,  and  from  this  point  of  view  the  question  assumes  a 
rather  different  aspect.  The  maximum  power  which  it  is 
advisable  to  develop  in  a  four-c^-cle  engine  is  relativelj'  small, 
and  as  to  multiply  the  number  of  cylinders  beyond  six  or 
eight  as  a  maximum  AAOuld  render  the  engine  unwieldy,  there 
comes  a  limiting  point  in  the  output  of  the  machine,  when 
it  is  no  longer  desirable  to  employ  the  four-cj'cle  principle, 
and  when  this  is  reached  it  is  well  to  sacrifice  the  small 


42   DIESEL  ENGINES  FOR  LAND  AND  MARINE  WORK 

difference  in  efficiency  between  tlie  two  types  for  greater 
convenience  of  operation.  Most  manufacturers  make  their 
standard  engines  of  the  four-stroke  type  up  to  about  700 
H.P.  to  1,000  H.P.,  above  which  power  the  two-stroke  single 
acting  machine  is  adopted.  Pursuing  this  line  of  argument 
further  it  might  be  deduced  that  for  the  very  largest  engines, 
the  two-stroke  double  acting  machine  is  the  ultimate  evolu- 
tion, but  this  is  apparently  not  necessarily  the  case.  Two- 
cycle  single  acting  Diesel  engines  have  ah'eady  been  con- 
structed, developing  1,200  H.P.  per  cylinder,  and  there 
would  seem  to  be  no  insuperable  difficulty  in  reaching  2,000 
H.P.  for  a  single  cylinder,  so  that  from  the  mere  question  of 
obtaining  a  large  output  the  double  acting  principle  is  not 
essential.  As  has  been  explained,  there  are  certain  difficul- 
ties to  contend  with  in  the  double  acting  type,  such  as  the 
question  of  cooling  the  piston  and  piston  rods,  and  the 
liability  of  trouble  with  tlie  piston  rod  stuffing  boxes,  which 
have  certainly  been  satisfactorily  overcome  by  some  manu- 
facturers, but  have  nevertheless  to  be  seriously  considered, 
and  must  be  recognized  in  deciding  on  the  relative  advan- 
tages of  the  machine.  There  is  also  the  point  that  such  large 
scavenge  cylinders  are  required  as  to  nuIUfy  partially  the 
advantage  gained  by  the  double  acting  engine  in  the  saving 
in  space  occupied  by  the  engine.  It  is  possible  that  for 
very  large  powers  for  stationary  work,  horizontal  double 
acting  engines  will  be  employed. 

In  the  two-cycle  single  acting  engine,  the  power  obtained 
per  cyhnder  is  theoretically  double  that  of  the  four  cycle, 
while  when  double  acting,  still  greater  powers  can  be  de- 
veloped, and,  of  course,  the  engine  is  lighter  for  the  same 
power.  The  theoretical  proportions  do  not  quite  coincide 
with  those  which  obtain  in  practice,  owing  to  the  impossi- 
bility of  the  efficient  employment  of  the  whole  of  the  cylin- 
der volume  in  two-cycle  engines.  This  is  brought  about  by 
the  necessity  for  exhaust  and  possibly  scavenge  ports  in  the 
cylinder  walls  and  in  any  comparison  between  the  two-cycle 
and  four-cycle  types  it  may  be  taken  generally  that  only  75 
to  80  per  cent,  of  the  cyhnder  volume  is  actually  usefully  em- 


ACTION  AND  WORKING  OF  THE  DIESEL  ENGINE     43 

ployed.  Olher  things  being  equal  it  would  seem  advisable 
to  adopt  the  two-cycle  type,  and  preferably  engines  working 
on  the  double  acting  principle,  but  there  are  however  many 
considerations  affecting  the  matter.  A  two-cycle  engine  can 
never  be  quite  so  efficient  as  one  working  on  the  four-cycle 
principle,  for  the  reason  that  the  entrance  of  the  scavenge 
air  does  not  permit  of  the  most  efficient  expansion,  and  there 
is,  of  course,  a  further  loss  of  power  in  driving  the  scavenge 
pump  ;  it  may  be  taken  as  a  general  rule  that  the  two-cycle 
engine  is  5  or  7  per  cent,  less  efficient  than  four  cycle,  which 
is  quite  sufficient  to  render  the  employment  of  the  latter 
advisable,  unless  the  space  available  for  the  engine  is  limited, 
since,  of  course,  the  four-cycle  engine  is  much  larger  than 
the  two  cycle. 

Considering  now  the  question  of  Diesel  marine  engines, 
the  four-cycle  machine  will  probably  be  replaced  for  verj' 
large  vessels  in  spite  of  its  high  efficiency.  Several  four- 
stroke  cycle  engines  have  been  built  for  marine  work  up  to 
1,500  H.P.,  but  that  this  practice  will  continue  for  verj^  large 
powers  is  far  from  likely,  and  it  has  probably  only  been  adopted 
since  so  much  experience  has  been  obtained  with  this  type 
and  it  was  desired  to  lessen  as  far  as  possible  what  might 
be  termed  the  experimental  nature  of  the  installation. 

For  marine  work  there  are  two  very  important  reasons 
which  render  the  two-cycle  engine  preferable  to  the  four- 
cycle, the  first  being  the  lesser  space  required  and  the  re- 
duction in  weight,  while  the  second  is  the  greater  ease  with 
which  it  is  possible  to  reverse  engines  working  on  this  cycle, 
compared  with  the  more  complicated  mechanism  and  com- 
parative difficulty  encountered  with  four-cycle  engines. 
There  is  a  still  further  point  in  favour  of  two-cycle  engines 
for  marine  work,  namety,  that  there  are  no  actual  exhaust 
valves  on  this  type,  but  only  ports  which  are  cleared  out  by 
scavenge  air  every  revolution  ;  hence  they  do  not  so  readily 
become  foul,  and  require  less  cleaning. 

Practically  the  only  parts  in  a  four-cycle  Diesel  engine 
which  require  attention  are  the  exhaust  and  fuel  valves,  and 
these  should,  if    possible,  be  cleaned  out  once  a  fortnight. 


44    DIESEL  ENGINES  FOR  LAND  AND  MARINE  WORK 

though  if  care  be  taken  that  the  exhaust  is  always  clear 
and  not  smoky,  the  exhaust  valve  may  be  in  operation  as 
long  as  six  months  without  cleaning.  Frequent  cleaning 
is  usually  inconvenient  with  vessels  making  long  voyages, 
though  various  means  can  be  devised  for  overcoming  the 
difficulty,  such  as  an  arrangement  for  shutting  off  the 
cylinders  separately  and  taking  out  the  fuel  valve  while  the 
engine  is  still  running,  which  method  has,  in  fact,  been 
actually  employed.  But  it  is  naturally  preferable  to  avoid 
the  necessity  of  cleaning  at  all  since  any  interference  with 
running  machinery  is  to  be  deprecated.  For  powers 
up  to  1,500  B.H.P.  or  2,000  B.H.P.,  however,  there  is  no 
doubt  still  a  wide  field  for  the  four-cycle  engine,  in  spite 
of  its  disability  as  regards  weight,  cost  and  complication, 
and  this  fact  has  been  amply  demonstrated  by  the  success 
which  has  attended  the  various  vessels  now  in  commission, 
propelled  by  four-cycle  Diesel  engines. 

The  question  resolves  itself  mainly  into  whether  the  double 
acting  or  the  single  acting  two-stroke  engine  should  be 
employed  for  large  powers,  and  it  should  be  mentioned  that 
many  firms  constructing  Diesel  engines  are  at  present 
averse  to  the  double  acting  principle,  although  engines  of  this 
type  are  now  running  satisfactorily.  Larger  powers  may  be 
obtained  per  cylinder,  and  in  fact  the  number  of  actual  work- 
ing cylinders  will,  generally  speaking,  be  only  one-half  that 
required  with  the  single  acting  engine  for  the  same  power  and 
turning  moment.  The  chief  objection  is  that  there  is  always 
a  certain  liability  of  danger  with  the  stuffing  boxes  of  the 
piston  rods,  which  is  sometimes  experienced  with  double 
acting  gas  engines,  and  the  trouble  is  likely  to  be  more 
acute  with  Diesel  engines  owing  to  greater  combined  tem- 
peratures and  pressures,  and  more  inequahty  in  the  pres- 
sures. The  double  acting  machine  is  in  some  ways  more 
complicated  than  the  single  acting,  and  though  this  is  not 
a  certain  preventative  against  its  success,  simpUcity  is 
to  be  desired  for  marine  engines,  and  the  questions  of  reha- 
biUty,  accessibility  of  parts,  and  ease  of  repairs  must  be 
carefully  attended  to,  in  any  design  which  is  to  meet  with 


ACTION  AND  WOKKING  OF  THE  DIESEL  ENGINE      45 

the  approval  of  the  marine  engineer.  With  double  acting 
engines  large  scavenge  pumps  are  required,  and  indeed 
compare  in  size  with  the  dimensions  of  the  working  cylin- 
ders, so  that  the  saving  in  space  and  weight  is  not  so  great 
as  might  at  first  sight  be  expected.  Moreover,  greater 
care  has  to  be  taken  with  regard  to  the  cooling  of  the 
pistons,  piston  rods,  exhaust  ports,  etc. 

With  a  double  acting  engine  it  is  impossible  to  arrange 
the  fuel  admission  in  the  centre  at  the  bottom  of  the  cylin- 
der owing  to  the  piston  rod  passing  through,  while  in  the 
horizontal  type  the  piston  rod  is  sometimes  arranged  to 
pass  through  the  cylinder  at  the  back  end  in  order  that 
the  weight  of  the  piston  may  be  supported.  This  leads 
to  the  necessity  for  admitting  the  fuel  eccentrically,  which 
is  probably  not  such  an  efficient  method,  and  moreover 
renders  the  valve  gear  considerably  less  simple,  and  the 
valves  at  the  bottom  are  not  easy  to  get  at  for  overhaul 
and  repairs.  If,  in  the  vertical  type,  fuel  is  admitted  in 
the  centre  at  the  top  and  eccentrically  at  the  bottom,  this 
causes  a  different  distribution  of  pressure  on  the  piston 
on  the  up  and  down  stroke  respectively  and  has  to  be  allowed 
for  in  the  design.  Another  point  which  to  some  extent 
places  the  double  acting  engine  at  a  disadvantage,  is  the 
fact  that  the  clearance  space  between  the  piston  and  cylinder 
cover  is  equally  important  at  each  end,  and  it  is  of  course 
impossible  to  adjust  both  ends  by  the  means  adopted  in 
the  single  acting  engine — namely  by  the  insertion  or  removal 
of  a  Imer  at  the  back  of  the  big  end  bearing -and  some  special 
arrangement  has  to  be  adopted. 

As  a  matter  of  fact  there  is  Uttle  reason  to  suppose  that 
either  the  single  or  double  acting  engine  should  be  adopted 
to  the  exclusion  of  the  other,  though  if  as  large  powers  as 
are  necessary  can  be  obtained  in  cylinders  working  on  the 
single  acting  principle,  the  main  object  of  the  double  act- 
ing type  is  destroyed.  Evidently  there  are  many  matters 
affecting  the  choice  of  type  for  marine  work,  quite  apart 
from  mere  theoretical  considerations,  and  the  only  safe  state- 
ment in  connexion  with  marine  work  is  that  the  widespread 


46   DIESEL  ENGINES  FOR  LAND  AND  MARINE  WORK 

adoption  of  the  two-cycle  type  is  extremely  probable 
once  the  experimental  stage  is  passed,  which  must  con- 
tinue for  a  few  years,  but  whether  the  single  acting  or 
double  acting  engine  will  find  general  favour  is  a  problem 
which  future  experience  alone  can  solve. 

Engine  Speeds. — It  was  at  one  time  thought  that  the 
speeds  of  Diesel  engines  to  give  maximum  economy  must 
be  slightly  higher  than  was  desirable  from  the  point  of 
view  of  propeller  efficiency,  particularly  for  the  slow  cargo 
vessel  for  which  this  motor  is  peculiarly  applicable.  It  would 
seem,  however,  from  recent  practical  experience  that  there 
is  very  little  reason  to  anticipate  that  the  Diesel  motor 
will  suffer  much,  if  at  all,  in  this  direction  in  comparison 
with  steam  engines,  although  many  of  the  earlier  motor  ships 
have  been  equipped  with  motors  running  at  a  speed  con- 
siderably in  excess  of  corresponding  steam  engines. 

The  difference  in  any  case  is  not  of  great  importance  from 
the  point  of  view  of  actual  overall  fuel  consumption,  but  at 
the  same  time  it  is  desirable  for  many  reasons  that  the  Diesel 
motor  should  conform  as  far  as  reasonable  with  existing 
marine  practice.  Engines  of  even  as  low  a  power  as  800 
H.P.  are  now  designed  to  run  at  100  revolutions  per  minute 
and  below,  and  recent  motors  of  2,000  H.P.  have  been 
designed  for  a  normal  speed  of  90  revolutions  per  minute  for 
vessels  of  about  10  to  12  knots.  It  has  also  been  found 
practicable  to  run  these  engines  at  a  minimum  of  25  to  30 
per  cent,  of  the  normal  speed  or  even  less,  which  is  sufficient 
flexibility  for  most  practical  purposes. 

The  Diesel  engine  therefore  satisfies  all  the  requirements 
as  far  as  speed  is  concerned,  but  nevertheless  in  certain  cases 
a  gear  reduction  has  been  employed,  in  some  instances  a 
mechanical  or  hydraulic  gear,  and  in  at  least  one  case,  an 
electric  transmission  system,  utilizing  high-speed  stationary 
Diesel  engines. 

Limiting  Power  of  Diesel  Engines. — One  of  the  chief 
difficulties  met  with  in  the  development  of  the  internal 
combustion  engine  was  the  trouble  in  producing  a  satis- 
factory  motor  of    large   power   without   a   multiplicity   of 


ACTION  AND  WORKING  OF  THE  DIESEL  ENGINE     47 

cylinders.  The  necessity  for  such  machines  led  to  the 
introduction  of  the  two-cycle  and  the  double  acting  gas 
engines,  chiefly  for  use  with  blast  furnace  gas,  and  the 
experience  gained  has  been  utilized  to  the  full  by  manu- 
facturers of  Diesel  engines.  Gas  engines  of  various  types 
are  now  built  up  to  4,000  B.H.P.  with  single  cylinders  of 
1,000  B.H.P.  each,  and  with  these  machines  no  insuperable 
difficulties  are  encountered  m  construction  or  operation. 
There  are  several  reasons  why  motors  working  on  the 
Diesel  cycle  should  be  capable  of  developing  larger  powers 
per  cylinder  than  gas  engines  operatmg  on  the  constant 
volume  cycle.  As  will  have  been  noticed  from  an  examina- 
tion of  the  indicator  cards  of  a  Diesel  engine,  the  mean 
effective  pressure  exerted  on  the  piston  is  far  higher  than 
in  a  gas  engine,  the  average  being  about  100  to  110,  and 
in  some  cases  even  125  lb.  per  sq.  inch,  against  60  to  70 
lb.  per  sq.  inch  mth  gas  engines.  For  equal  cyhnder  vol- 
umes a  Diesel  engine  will  thus  give  a  higher  power  than 
a  gas  engine.  The  temperature  rise  has  probably  the  most 
important  influence  m  hmiting  the  size  of  engine  cylinders 
and,  as  has  been  seen,  this  is  less  with  Diesel  than  mth  gas 
engines,  while  the  clearance  volume  in  the  former  is  also 
well  below  that  of  the  latter,  being  some  6  to  8  per  cent, 
against  25  per  cent,  or  more  with  four-cycle  engines,  though 
the  proportion  does  not  quite  hold  in  larger  powers,  and 
with  the  two-cycle  type.  It  is  difficult  at  the  present 
time  to  say  exactly  what  is  the  maximum  power  that 
could  safely  be  developed  in  a  single  cyhnder  of  a  Diesel 
engine,  and  the  point  cannot  be  satisfactorily  settled 
until  further  experience  has  been  gained.  The  piston 
diameter  cannot  be  very  largel}^  increased  owing  to  the 
high  compression  pressure  and  the  consequently  excessive 
resultant  pressures  on  the  connecting  rod  and  crank, 
while  with  very  large  cylinder  diameters  the  question  of 
efficiently  coohng  the  piston  rod  becomes  somewhat  trouble- 
some. 

The  point  is  chiefly  of  importance  in  connexion  with  the 
marine  engine,  smce  it  is  safe  to  say  that  Diesel  engines  of 


4S    DIESEL  ENGINES  FOR  LAND  AND  MARINE  WORK 

the  stationary  type  can  now  be  built  up  to  any  power  that 
may  be  reasonably  required.  In  view  of  the  experience 
already  gained  with  large  engines  the  opinion  of  designers 
is  that  no  insuperable  difficulties  will  be  encountered  in 
building  Diesel  engines  developing  2,000  H.P.  per  cylinder 
working  on  the  two-cycle,  single  acting  principle,  or  4,000 
H.P.  for  double  acting  machines  ;  as  a  matter  of  fact,  two 
three-cylinder,  double  acting,  two-cycle  engmes  of  more  than 
8,000  H.P.  each  have  already  been  built  and  run  satisfac- 
torily, one  of  the  engines  developing  nearly  2,800  H.P.  per 
cylinder.  Engines,  therefore,  of  15,000  to  20,000  H.P.  are 
quite  within  the  bounds  of  immediate  possibility.  In  all 
probabiUty  engines  of  nearly  4,000  H.P.  per  cylinder  will 
be  built  within  a  short  time  which  would  allow  the  highest 
powers  at  present  required  to  be  obtained. 

Weights  of  Diesel  Engines. — One  point  of  great  interest 
in  connexion  with  a  comparison  between  the  various  types 
of  Diesel  engines  is  the  weights  of  the  different  motors, 
referring  for  the  moment  to  stationary  engines,  since  marine 
engines  are  dealt  with  separately  in  the  section  on  marine 
Diesel  motors.  Economy  in  Aveight  is  advantageous  in 
i^arious  directions,  not  the  least  being  that  it  allows  of 
considerable  reduction  in  cost  which  has  always  been  of 
great  moment  in  oil  engines  of  the  high  compression  type. 

The  following  tables  which  give  actual  weights  of  some 
of  the  M.A.N,  engines,  do  not  apply  generally  to  all  designs, 
but  the  variations  are  not  large  and  the  figures  are  suffi- 
ciently accurate  for  comparisons.  Horizontal  motors  are 
lighter  than  those  of  the  vertical  type  and  vertical  two- 
cycle  engines  do  not  shew  quite  so  favourably  as  the  hori- 
zontal ones,  although  nearly  so.  The  weights  given  are 
sufficient  to  show  how  it  is  possible  to  manufacture  a  two- 
cycle  Diesel  motor  at  a  price  of  from  £6  to  £8  per  B.H.P., 
whereas  the  four-cycle  type  costs  nearly  £10  per  B.H.P. 
even  in  the  larger  sizes. 


ACTION  AND  WORKING  OF  THE  DIESEL  ENGINE     49 


Weights  of  Four-Cylinder  Diesel  Motors. 


CyHn- 

der 
Diam. 
Inches. 

Piston 
Stroke. 
Inches. 

Revs, 
per 
Min. 

B.H.P. 

Weight. 
Lbs. 

Lbs. 

per 

B.H.P. 

Type. 

13-6 

19-3 

195 

200 

65,560 

328 

4-cycle  vertical  single- 

17  7 

24-9 

175 

400 

118,880 

299 

acting. 

Ditto 

21  0 

291 

167 

600 

187,000 

312 

Ditto 

25-2 

35-4 

150 

1,000 

339,900 

340 

Ditto 

230 

31-4 

150 

1,200 

308,000 

257 

4-cycle     horizontal 
double-acting 

290 

39-4 

125 

2,000 

479,600 

240 

Ditto 

360 

51  0 

94 

3,000 

785,400 

262 

Ditto 

39-4 

550 

£4 

4,000 

913,000 

228 

Ditto 

169 

251 

187 

400 

110,000 

275 

4-cycle     horizontal 

18-9 

27-5 

167 

500 

145,200 

290 

single-acting 
Ditto 

200 

291 

167 

600 

165,000 

275 

Ditto 

210 

30-6 

167 

700 

189,200 

270 

Ditto 

* 
19-6 

29-5 

167 

1,000 

154,000 

154 

2-cycle     horizontal 

24-3 

31-4 

150 

1,500 

242,000 

161 

single-acting 
Ditto 

26-3 

35-4 

150 

2,000 

330,000 

165 

Ditto 

Fuel  for  Diesel  Engines. — Speaking  generally,  it  may 
be  said  that  practically  any  kind  of  oil  can  be  employed 
with  Diesel  engines.  The  chief  among  those  at  present 
produced  and  obtainable  in  large  quantities  are  the  natural 
oils  from  the  oil  wells  now  productive  in  all  parts  of  the 
world,  and  the  oils  resulting  from  the  distillation  of  coal 
and  brown  coal  or  Ugnite.  There  has  been  some  question 
as  to  whether  the  increasmg  employment  of  the  Diesel 
engine  will  not  result  in  a  shortage  of  supply  of   oil  and  a 


50   DIESEL  ENGINES  FOR  LAND  AND  MARINE  WORK 

consequent  increase  of  price,  which  would  at  once  diminish 
the  great  advantage  of  economy  now  possessed  by  this 
motor.  When,  however,  it  is  considered  that  the  world's 
output  of  oil  from  the  wells  is  in  the  neighbourhood  of 
fifty  million  tons  annually  and  that  this  figure  is  rising 
rapidly  it  is  difficult  to  imagine  that  this  anticipation  will 
be  in  any  way  fulfilled.  At  the  present  time  all  the  Diesel 
engines  extant  consume  only  quite  a  minute  proportion 
of  the  world's  supply,  and  moreover  it  is  the  general 
opinion  of  geologists  that  there  are  vast  oil-fields  in 
many  parts  of  the  globe  which  have  not  yet  been  ex- 
ploited, and  that  the  supply  from  these  is  wellnigh  un- 
limited. It  seems  therefore  that  in  the  future,  by  the  very 
fact  of  the  wide  demand  for  crude  oils,  the  production  will 
largely  increase  and  the  tendency  of  the  price  of  oil  will 
be  to  drop  rather  than  to  rise.  There  seems  little  doubt 
that  the  occurrence  of  oil  is  about  as  widespread  as  coal, 
and  hence  any  large  permanent  increase  in  the  cost  of  the 
former  is  less  lil^ely  than  in  the  latter.  There  will  be,  and 
have  been,  temporary  and  artificial  fluctuations  in  the  price 
owing  to  the  conditions  under  which  oil  is  marketed,  but 
too  much  importance  should  not  be  laid  on  this  point,  al- 
though it  may  at  times  detrimentally  affect  the  development 
of  Diesel  engines. 

There  is,  however,  this  fact  to  be  remembered,  that  most 
of  the  countries  in  which  machinery  is  most  largely  required 
— namely,  in  many  parts  of  Europe — are  not  oil-producing 
lands,  and  hence  are  dependent  on  their  supply  of  natural 
oil  from  outside  sources.  This  is  a  matter  of  no  great 
importance  in  Great  Britain  and  other  countries  such  as 
Belgium,  Denmark  and  Sweden,  where  there  is  no  duty  on 
imported  oil,  but  makes  a  vast  difference  in  Germany, 
France,  Italy  and  Spam  where  the  duty  is  high,  this  being 
particularly  the  case  in  the  two  first  named,  and  in  France 
it  is  such  as  wellnigh  to  prohibit  the  use  of  Diesel  engines 
running  on  crude  oils. 

The  matter  can  be  well  explained  by  a  statement  of 
the   price   of   residue    oil  which  at    present   obtains.       Its 


ACTION  AND  WORKING  OF  THE  DIESEL  ENGINE     51 

approximate  value  near  the  oilfields  is  155.  to  2os.  per 
ton,  and  delivered  at  a  European  port  it  should  be  about 
455.  to  (50s.  per  ton.  In  Germany  the  duty  is  about  36s.  per 
ton,  or  nearl}^  equivalent  to  the  actual  value  of  the  oil, 
which  renders  the  fuel  cost  of  a  Diesel  engine  running 
on  natural  oil  much  higher  than  it  is  in  this  country. 
For  this  reason  much  attention  has  been  paid  in  Germany 
and  elsewhere  to  the  question  of  emplopng  other  oils, 
and  those  produced  by  the  distillation  of  coal,  and  lignite  or 
brown  coal,  of  which  large  quantities  are  available,  are  being 
much  used.  The  lignite  oils  are  in  every  way  suitable 
for  Diesel  engines  and  have  been  employed  for  many  years, 
but  the  price  of  these  oils  again  is  high  (75  marks  per  ton) 
and  very  httle  saving  is  effected  as  compared  with  the 
imported  residue  oils. 

The  oil  from  the  distillation  of  coal  is  very  much  more 
largely  produced  in  Germany  than  lignite  oil,  nearly  twice 
the  amount  beuig  available  for  sale  at  a  price  of  less  than 
40s.  per  ton.  The  difficulty  original^  experienced  m  the 
use  of  this  coal  tar  oil  for  Diesel  engmes  was  its  high  flash 
point,  which  is  about  400°  Fahr.  or  over,  and  with  the 
ordinary  construction  this  would  necessitate  a  considerably 
higher  compression  pressure  in  the  cylinder  for  its  ignition 
than  the  residue  oil  with  a  flash  point  of  under  230°  Fahr. 
In  order  to  avoid  this  high  compression  an  arrangement 
has  now  been  generally  adopted  which  has  proved  in  every 
way  satisfactory,  of  injecting  a  small  amount  of  crude  oil 
into  the  cylinder  through  the  pulveriser  immediately  before, 
or  simultaneously  with,  the  main  charge  of  coal  tar  oil, 
the  quantity  usually  admitted  being  from  5  to  10  per  cent, 
of  the  total  weight  of  fuel.  Even  this  is  not  always 
nececsary  if  pre-heating  is  adopted. 

Combustion  takes  place  with  the  fuel  first  injected,  and 
the  resultant  temperature  is  sufficient  to  ignite  the  oil  of 
higher  flash  pomt  when  it  enters  without  any  higher  com- 
pression pressure  being  necessary.  The  same  fuel  valve 
may  be  used  for  both  injections  and  is  suitable  without 
any  alteration   for  all   other  oils.     This   arrangement   has 


52    DIESEL  ENGINES  FOR  LAND  AND  IHARINE  WORK 

worked  very  succevSsfuUy  and  is  now  very  widely  adopted. 
The  calorific  value  of  coal  tar  oil  is  about  16,000  B.Th.U. 
per  lb.  as  against  18,000  to  19,000  B.Th.U.  of  the  crude  or 
residual  oils,  and  the  consumption  in  a  Diesel  engine  of 
moderate  power  at  full  load  is  slightly  higher  than  with 
the  natural  oils,  in  the  inverse  proportion  of  the  respective 
calorific  values,  being  usually  about  0-45  lb.  per  B.H.P.  hour 
for  engines  of  moderate  power. 

The  oil  which  is  utilized  for  Diesel  engines  in  this  country 
and  in  all  oil-producing  countries,  or  countries  in  which 
there  is  no  duty  levied,  is  th?  so-called  crude  or  residual 
oil.  This  is  obtained  by  the  distillation  of  the  oil  from 
the  well,  the  lighter  bodied  oils,  benzine  and  lighting  petro- 
leum coming  over  first  and  leaving  a  residual  oil.  Its 
specific  gravity  is  usually  between  -85  and  •1)2.  and  owing 
to  its  high  flash  point  it  is  quite  unsuited  for  lamp  oil  or 
for  use  in  most  explosion  engine:>,  such  as  petrol  motors, 
though  useful  for  such  engines  as  the  Brons  and  Bolinder. 

Whilst  the  question  of  the  price  of  fuel  oil  for  Diesel 
engines  is  one  of  very  great  importance,  it  wdll  never  affect 
the  prosperity  of  the  Diesel  engine  industry  in  a  vital  degree, 
however  high  it  may  rise,  since,  as  shown  later,  the  fuel 
economy  with  this  type  of  moto'  is  not  its  sole  claim  for 
consideration. 

A  very  large  number  of  different  oils  are  now  employed 
for  the  operation  of  Diesel  engines,  among  which  may  be 
mentioned  the  crude  oil  from  Texas  and  Tarakan,  and  the 
residual  oil  from  numerous  other  countries.  Calif ornian 
oil,  Roumanian  oil  and  that  from  the  Galician  fields 
have  been  commonly  utilized  for  a  number  of  years,  while 
recently,  owing  to  the  enormous  supplies  which  are  now 
available  from  Mexico,  the  Mexican  oil  has  also  been  used. 
Trinidad  oil  is  now  iqDon  the  market,  as  is  that  from  Persia, 
so  that  there  is  a  wide  choice. 

There  is  not  much  to  say  as  regards  their  composition, 
since  practically  all  of  them  are  entirely  suitable  for  the 
Diesel  engine  of  every  type.  The  only  point  to  note  is 
that  those  which  have  an  asphalt  base  are  liable  to  leave 


ACTION  AND  WORKING  OF  THE  DIESEL  ENGINE     53 

a  considerable  amount  of  ash  on  the  valves,  and  are  there- 
fore not  quite  so  good  as  the  others  which  are  not  from  an 
asphalt  base.  The  Mexican  oil  is  perhaps  one  of  the  worst 
in  this  direction.  As  regards  the  question  of  sulphur, 
which  many  people  considered  a  serious  and  detrimental 
constituent  in  oil  for  Diesel  engines,  it  has  now  been  showii 
by  a  large  number  of  experiments  that  its  real  effect 
(even  when  it  is  present  in  the  oil  to  the  extent  of  4  or  5 
per  cent.)  is  practically  negligible.  This  arises  mainly 
from  the  fact  that  there  is  no  moisture  present  in  the  Diesel 
engine  cylinder,  and  that  without  moisture  no  liquid 
sulphuric  acid  is  formed,  which  is  the  main  cause  of 
trouble  due  to  the  presence  of  sulphur.  So  clearly  is  this 
view  now  held,  that  the  Admiralty  specification  for  oil  has 
been  altered  to  suit  the  new  ideas  upon  the  subject.  The 
specific  gravity  of  most  oils  which  are  used  in  Diesel  engines 
varies  between  0-9  and  0-97;  the  flash-point  is  generally 
from  220^  to  250'  Fahr. 

Further  interesting  details  witli  regard  to  the  employ- 
ment of  fuel  oil  for  Diesel  engines  may  be  obtained  from  Dr. 
Sommer's  book  dealing  with  the  subject,  Petroleum  as  a 
Source  of  Power  on  Ships,  from  which  the  following  table 
is  extracted  : — 


1 
S.P.G. 

Be. 

Gross  Heating  Value 
by  Experiment. 

Per 
cent. 

Cals. 

B.T.U's. 

Roumanian  gas  oil 

0-871 

31-9 

10,712 

19,282 

100 

Admiralty  fuel. 

0-907 

24-25 

10,696 

19,253 

99-8 

Roumanian  fuel 

0-927 

20-95 

10,557 

19,003 

98-5 

Roumanian  residuiun  . 

0-928 

20-8 

10,558 

19,004 

98-5 

Trinidad  crude  oil 

0-94.5 

1805 

10.200 

18.360 

95-2 

Roumanian  residuum 

0-946 

17-9 

10,510 

18,918 

98- 1 

Tarakan  crude  oil 

0-948 

17-6 

10,487 

18,877 

97-8 

Trinidad  residuum 

0-964 

15-5 

10,224 

18,405 

95-4 

The    British    Admiralty    issues    a    specification    for   fuel 


54   DIESEL  ENGINES  FOR  LAND  AND  MARINE  WORK 

oil  which  has  comparatively  recently  been  modified,  and 
now  stands  as  follows  : — 

"  Quality  : — The  oil  fuel  supplied  shall  consist  of  liquid 
hydrocarbons,  and  may  be  either  (a)  shale  oil  or  (6) 
petroleum  as  may  be  required,  or  (c)  a  distillate  or  a  residual 
product  of  petroleum,  and  shall  comply  with  the  Admiralty 
requirements  as  regards  flash-point,  fluidity  at  low  tempera- 
tures, percentage  of  sulphur,  presence  of  water,  acidity, 
and  freedom  from  impurities. 

"  The  flash-point  shall  not  be  lower  than  175°  Fahr.,  close 
test  (Abel  or  Pensky-Matens).  (This  compares  with  a  flash- 
point of  200°  Fahr.  in  1910.) 

"  The  proportion  of  sulphur  contained  in  the  oil  shall  not 
exceed  300  per  cent,  (as  against  0-75  in  1910). 

"  The  oil  fuel  supplied  shall  be  as  free  as  possible  from  acid, 
and  in  any  case  the  quantity  of  acid  must  not  exceed  0-05 
per  cent.,  calculated  as  oleic  acid  when  tested  by  shaking 
up  the  oil  with  distilled  water,  and  determining  by  titration 
with  deci-normal  alkali  the  amount  of  acid  extracted  by 
the  water,  methyl  orange  being  used  as  indicator.  (In 
1910  it  was  required  that  the  oil  should  be  free  from  acidity. ) 

"  The  quantity  of  water  delivered  with  the  oil  shall  not 
exceed  0-5  per  cent. 

"  The  viscosity  of  the  oil  supplied  shall  not  exceed  2,000 
sees,  for  an  outflow  of  50  cubic  centimetres  at  a  temperature 
of  32°  Fahr.,  as  determined  by  Sir  Boverton  Redwood's 
standard  viscometer  (Admiralty  type  for  testing  oil  fuel). 

"  The  oil  supplied  shall  be  free  from  earthy,  carbonace- 
ous, or  fibrous  matter,  or  other  impurities  which  are  likely 
to  choke  the  burners. 

"  The  oil  shall,  if  required  by  the  inspecting  officer,  be 
strained  by  being  pumped  on  discharge  from  the  tanks, 
or  tank  steamer,  through  filters  of  wire  gauze  having  16 
meshes  to  the  inch. 

"  The  quality  and  kind  of  oil  supplied  shall  be  fully  de- 
scribed. The  original  source  from  which  the  oil  has  been 
obtained  shall  be  stated  in  detail,  as  well  as  the  treatment 
to  which  it  has  been  subjected  and  the  place  at  which  it  has 


ACTION  AND  WORKING  OF  THE  DIESEL  ENGINE     55 

been  treated.  The  ratio  which  the  oil  supplied  bears  to  the 
original  crude  oil  should  also  be  stated  as  a  percentage." 
In  view  of  the  widespread  employment  of  tar  oil  in  Ger- 
many, and  its  probable  utilization  in  this  coimtry  in  the 
future  on  a  much  larger  scale,  the  specification  of  this  tar 
oil  which  is  supplied  by  a  large  company  in  Germany  is 
worthy  of  quotation. 

Specification  of  Tar  Oil  Suitable  for  Diesel  Engines. 

(From  the  German  Tar  Production  Syndicate  of  Essen- 
Ruhr.) — (1)  Tar-oils  should  not  contain  more  than  a  trace 
of  constituents  insoluble  in  xylol.  The  test  on  this  is  per- 
formed as  follows: — 25  grammes  (0-88  ounce  av.)  of  oil 
are  mixed  with  25  grammes  (1-525  cub.  inch)  of  xylol 
shaken  and  filtered.  The  filter-paper  before  being  used  is 
dried  and  weighed,  and  after  filtration  has  taken  place  it 
is  thoroughly  washed  with  hot  xylol.  After  redrying  the 
weight  should  not  be  increased  by  more  than  0-1  gramme. 

(2)  The  water  contents  should  not  exceed  1  per  cent. 
The  testing  of  the  water  contents  is  made  by  the  well- 
known  xylol  method. 

(3)  The  residue  of  the  coke  should  not  exceed  3  per  cent. 

(4)  When  performing  the  boiling  analysis,  at  least  60 
per  cent,  by  volume  of  the  oil  should  be  distilled  on  heating 
up  to  300°  C.  The  boiling  and  analj^sis  should  be  carried 
out  according  to  the  rule  laid  down  by  the  Syndicate. 

(5)  The  minimum  calorific  power  must  not  be  less  than 
8,800  cal.  per  kg.  (15,800  B.T.U.'s  per  lb.).  For  oils  of  less 
calorific  power,  the  purchaser  has  the  right  of  deducting  2 
per  cent,  off  the  net  price  of  the  delivered  oil  for  each  cal. 
below  this  minimum. 

(6)  The  flash-point,  as  determined  in  an  open  crucible 
by  Von  Holde's  method  for  lubricating  oils,  must  not  be 
below  65°  C. 

(7)  The  oil  must  be  quite  fluid  at  15°  C.  The  purchaser 
has  not  the  right  to  reject  oils  on  the  ground  that  emulsions 
appear  after  five  minutes'  stirring  when  the  oil  is  cooled 
to  8°. 


56   DIESEL  ENGINES  FOR  LAND  AND  MARINE  WORK 

Purchasers  should  be  urged  to  fit  their  oil-storing  tanks 
and  oil  pipes  with  warming  arrangements  to  redissolve 
emulsions  caused  by  the  temperature  falling  below  15°  C. 

(8)  If  emulsion  has  been  caused  by  the  cooling  of  the 
oils  in  the  tank  during  transport,  the  purchaser  must  re- 
dissolve  them  by  means  of  this  apparatus. 

Insoluble  residues  may  be  deducted  from  the  weight  of 
oil  supplied. 


CHAPTER    III 
CONSTRUCTION    OF    THE   DIESEL    ENGINE 

GENERAL    REMARKS FOUR-CYCLE     SINGLE    ACTING    ENGINE  ; 

GENERAL     ARRANGEMENT STARTING     AND      RUNNING 

DESCRIPTION  OF  FOUR-CYCLE  ENGINE — VALVES  AND 
CAMS REGULATION  OF  THE  ENGINE TYPES  OF  FOUR- 
CYCLE    ENGINES — HIGH     SPEED       ENGINE HORIZONTAL 

ENGINE TWO-CYCLE       ENGINE AIR    COMPRESSORS    FOR 

DIESEL   ENGINES SOLID    INJECTION    MOTORS. 

General  Remarks. — In  the  manufacture  of  Diesel 
engines  there  is  one  point  which  must  be  most  strongly 
kept  in  view,  this  being  that  greater  care  has  to  be  taken 
in  their  construction  than  with  ordinary  steam  engines. 
A  properly  designed  and  well-built  Diesel  engme  has  no 
superior,  for  reUability  and  simpUcitj^  of  operation,  but  it 
i?  essential  that  the  materials  employed  should  be  well 
selected,  the  work  should  be  of  the  best,  and  the  greatest 
precision  should  be  exercised  in  the  fitting  of  the  valves 
and  gear,  and  other  mechanism.  It  might  be  thought  that 
these  matters  need  no  emphasis,  but  the  difference  in  the 
running  of  an  engine  under  working  conditions,  which  has 
been  built  as  a  Diesel  engine  should  be,  and  one  which  has 
been  constructed  with  no  more  care  than  is  given  to  a 
similar  steam  engine  is  so  material  that  no  excuse  need  be 
made  for  enlarging  on  tliis  point. 

It  is  a  well-knoA^-n  axiom  in  the  manufacture  of  internal 
combustion  engines  that  in  the  attention  to  details  of  design 
and  construction  Ues  the  difference  between  success  and 
failure ;    and   this   is   peculiarly   applicable   to   the   Diesel 


58    DIESEL  ENGINES  FOR  LAND  AND  MARINE  WORK 

engine,  whose  satisfactory  running  depends  so  entirely  on 
the  high  compression  pressure  in  the  cylinder. 

Practically  aU  manufacturers  of  Diesel  engines  now  make 
them  in  standard  sizes  and  types,  which  is  rendered  com- 
paratively easy  by  the  fact  that  the  larger  machines  have 
two,  three,  four,  or  more  cylinders  of  the  smaller  standard 
type.  By  this  means  some  of  the  chief  manufacturers  have  as 
many  as  fifty  standard  stationary  machines  of  the  four-cycle 
type  from  10  H.P.  to  1,000  H.P.  based  on  some  fifteen  stand- 
ard single-cyhnder  engines  ranging  from  10  H.P.  to  250  H.P. 
Some  of  the  engines  have  the  same  power  with  a  different 
number  of  cylinders,  but  it  is  possible  with  this  range  to  have 
some  thirty-five  differently  rated  engines,  though  there  are 
only  fifteen  actual  standards.  This  point  of  standardization 
is  of  the  utmost  importance  as  regards  reduction  in  cost  of 
construction,  interchangeability  of  parts  between  different 
engines,  and  reduction  of  spare  gear  in  complete  installations, 
particularly  when  engines  of  different  powers  are  employed  ; 
these  advantages  will  be  readily  appreciated  by  all  who 
have  had  experience  with  the  operation  of  large  plants.  It 
is  doubtful  if  in  any  other  construction  this  matter  has 
received  such  attention,  and  if,  as  should  be  the  case,  all 
the  important  portions  of  the  engine  are  made  most  care- 
fully to  gauge,  any  part  of  the  mechanism  may  be  taken 
from  one  engine  and  fitted  on  to  another  of  the  same  class. 
Most  manufacturers  claim  that  this  is  possible  with  all  their 
engines,  and  some  of  them  make  a  point  of  interchanging 
the  parts  of  several  engines  when  on  the  test  bed,  to  prove 
the  point. 

Four -Cycle  Single  Acting  Engine. — Figs.  14  and  15 
show,  diagrammatically,  in  plan  and  elevation,  the  general 
arrangement  of  a  vertical  single-cylinder  Diesel  engine  of 
the  ordinary  type  with  all  the  necessary  accessories.  The 
cylinder  K  is  cast  with  the  engine  frame  of  the  A  type, 
being  secured  to  the  bed-plate  B  by  long  bolts.  The 
cyhnder  cover  K^  is  of  massive  construction  separate  from 
the  main  cylinder  and  frame  casting,  and  contains  all  the 
valves,  of  which  there  are  four.     A  is  the  starting  valve. 


CONSTRUCTION   OF  THE  DIESEL  ENGINE        59 

connected  by  piping  to  the  starting  vessels  Co  and  C^ ; 
D  is  the  exhaust  valve  through  which  the  exhaust  gases 
pass  from  the  cylinder  into  the  exhaust  pipe  E  and  thence 
to  the  silencer  F  (often  placed  below  ground  level),  to 
which  is  attached  the  long  pipe  0  for  the  escape  of  the  gases 
to  the  atmosphere  ;  H  is  the  air  suction  inlet  valve  by 
which  air  is  drawn  into  the  cylinder  from  the  engine-room 
through  the  inlet  pipe  J  of  special  construction  ;  X  is 
the  fuel  inlet  valve  and  pulveriser,  the  function  of  which 
is  to  admit  fuel  to  the  cylinder  at  the  right  moment  and  in 
the  form  of  a  fine  spray.  The  oil  reaches  the  fuel  valve 
from  the  fuel  pump  L,  whose  action  is  controlled  by  the 
governor,  the  fuel  pump  chamber  being  a  small  reservoir 
into  which  the  oil  gravitates  from  the  fuel  filter  M.  The 
fuel  pipe  is  also  arranged  that  it  may  take  its  supply  from 
another  small  cylindrical  vessel  N  which  usually  contains 
paraffin,  since  it  is  an  advantage  to  run  the  engine  for  a 
few  minutes  every  day  on  paraffin,  which  is  most  helpful 
in  cleaning  the  cylinder  and  valves.  The  fuel  filter  itself 
is  connected  by  a  pipe  from  a  larger  oil  reservoir  0,  fixed 
at  a  rather  higher  level,  and  it  is  convenient  to  have  this 
reservoir  of  such  size  as  will  contain  several  days'  supply. 
The  main  oil  tanks  containing  perhaps  several  months' 
supply  are  commonly  fixed  miderground  and  the  oil  is 
pumped  up  into  the  reservoir  as  required  by  a  small  pump 
which  may  be  driven  in  any  convenient  manner.  The  cool- 
ing water  circulation  is  arranged  so  that  the  water  enters  the 
jacket  through  a  pipe  at  the  bottom  and  leaves  at  the  top 
from  the  cylinder  cover.  This  pipe  is  usually  broken,  the 
water  flowing  into  an  open  funnel,  this  forming  a  ready 
means  of  ascertaining  that  there  is  no  stoppage  in  the  circu- 
lation. In  some  cases,  however,  water  is  expensive  and 
a  cooling  tower  is  installed  so  that  the  suppty  may  be  used 
continuously,  and  in  this  event  the  circuit  is  usually  a 
closed  one  ;  it  is  preferable  wherever  possible  to  employ 
open  circuit  piping,  and  in  any  case  a  thermometer  should 
be  fixed  on  each  cyhnder  to  indicate  the  temperature  of 
the  cooling  water.     Referring  to  Figs,  li^and    15  again,  P 


60   DIESEL  ENGINES  FOR  LAND  AND  MARINE  WORK 


represents  the  air 
compressor  shown 
as  being  driven 
off  the  engine 
crank  shaft 
(though  there  are 
various  other 
methods),  and  de- 
livering air  at  the 
high  pressure 
needed  for  fuel  in- 
jection and  start- 
ing the  engine 
into  the  air  reser- 
voir Ci  containing 
the  air  for  the  in- 
jection of  the  fuel. 
AU  the  air  vessels 
Ci,  C2  and  C3  are 
connected  by  air 
piping  and  valves 
so  that  the  pres- 
sure in  any  one 
may  be  lowered 
by  abstrac  ting 
from  either  of 
the  others  ;  of  the 
two  reservoirs  O2 
and  Cz  one  may 
be  considered  as  a 
spare  to  the  other. 
During  the  run- 
ning of  the  engine, 
the  only  air  used 
is,  of  course,  that 
necessary  for  the 
fuel  injection  and 
hence     the     com- 


FiG.  15.  — General 
Arrangement  of  Die- 
sel Plant — Elevation. 


FiQ.  14. — General  Arranfrement  Plan  of  Diesel  Plant. 


CONSTRUCTION   OF  THE   DIESEL  ENGINE        61 

pressor  delivers  its  air  directly  into  the  reservoir  Ci, 
the  valves  being  regulated  to  suit  the  required  pressure, 
but  at  the  same  time  the  starting  vessels  are  replen- 
ished so  that  there  is  always  an  efficient  supply  for 
re-starting  the  engine.  The  vertical  governor  shaft  R 
shown  in  the  figures  is  driven  through  worm  gearing  off 
the  crank  shaft,  and  this  through  further  gearing  drives 
the  horizontal  cam  shaft  *S,  supported  between  two  bearings 
mounted  on  the  C3dinder  casting,  and  on  which  are  all  the 
cams  for  operating  the  various  valves  in  the  cylinder  cover. 
The  governor  shaft  also  actuates  the  fuel  pump  L  and  the 
governor,  the  combined  action  of  which  regulates  the  speed 
of  rotation  of  the  engine.  The  cams  and  valve  levers  which 
they  control  are  not  shown  in  Figs- 1 4  and  IG  but  the  valves 
are  in  the  relative  positions  most  commonly  adopted  as 
being  best  suited  for  the  arrangement  of  the  four  cams 
on  the  cam  shaft.  The  exhaust  and  air  suction  inlet 
valves  are  on  the  outside  (longitudinally),  while  the  fuel 
and  starting  valves  are  close  together,  the  object  being 
to  have  their  levers  interconnected  so  that  it  is  impossible 
for  the  two  valves  to  be  open  at  the  same  time.  The  fuel 
valve  is,  of  course,  in  the  centre  of  the  cylinder  cover,  and 
thus  allows  the  oil  to  enter  centrally  and  give  an  equal  dis 
tribution  of  pressure  over  the  piston  during  combustion. 

A  third  outer  bearing,  separate  from  the  engine  bed-plate 
is  always  provided,  with  the  flywheel  T,  mounted  between 
this  and  the  inner  crank  shaft  bearing.  Diesel  engines  are 
never  constructed  as  two  bearing  machines  with  an  over- 
iiung  flywheel. 

Starting  and  Running. — The  starting  and  running  oi 
the  engine  is  as  follo\\s  :  The  starting  lever  on  the  engine 
is  put  in  the  starting  position,  that  is,  so  that  the  lever 
actuating  the  fuel  valve  is  out  of  operation  and  the  fuel 
valve  remains  closed,  whilst  the  lever  actuating  the  start- 
ing valve  on  the  cylinder  is  in  its  working  position,  that  is, 
it  is  moved  by  its  cam  on  the  cam  shaft  as  it  revolves  and 
thus  opens  the  starting  valve.  The  engine  is  barred  round 
till  it  is  just  over  the  dead  centre,  the  fuel  valve  is  pumped 


G2     DIESEL  ENGINES  FOR  LAND  AND  MARINE  WORK 

up  by  hand  to  ensure  the  oil  piping  is  full  of  oil,  and  the  air 
blast  valve  on  the  reservoir  Oi  is  opened  so  that  there  is 
a  supply  of  high  pressure  air  on  the  fuel  valve  when  it  is 
ready  to  open.  The  valve  on  the  starting  reservoir  which 
is  to  be  used  is  then  opened  and  the  engine  starts  up  as 
a  compressed  air  engine.  It  is  allowed  to  make  two  or 
three  revolutions  when  the  starting  handle  is  moved  so 
that  the  lever  operating  the  starting  valve  on  the  engine 
is  no  longer  moved  by  its  cam,  and  the  valve  thus  remains 
closed,  while  the  same  operation  brings  the  fuel  valve 
lever  into  working  position,  and  thus  opens  the  fuel  valve 
as  the  cam  operating  it,  comes  round.  The  arrangement 
is  such  that  when  the  starting  handle  is  in  the  starting 
position  the  lever  oj^erating  the  fuel  valve  is  held  well  out 
of  the  range  of  its  cam  on  the  cam  shaft,  while  \\  hen  the 
starting  lever  is  pushed  back  to  the  running  position  the 
lever  operating  the  starting  valve  is  similarly  held  away 
from  its  cam. 

Description  of  Four- Cycle  Single  Acting  Engine. — 
Figs  16  and  17  show  longitudinal  and  transverse  sectional 
elevations  of  a  single-cylinder  Diesel  engine  of  the  ordinary 
slow  speed  four-cycle  single  acting  type  as  constructed 
by  the  Maschinenfabrik  Augsburg  Niirnberg  A.G.  All 
the  four  valves  are  arranged  in  the  cylinder  head,  the  air 
inlet  suction  valve  E  and  the  exhaust  valve  A  being  simi- 
lar. These  are  of  the  mushroom  type,  opening  down- 
wards directly  into  the  cylinder,  and  they  are  kept  on  their 
seats  by  strong  springs,  the  pressure  on  which  may  be  regu- 
lated if  required.  The  outlet  from  the  exhaust  valve  is 
connected  by  piping  to  the  silencer,  while  to  the  air  suction 
inlet  is  coupled  a  pipe  through  which  the  air  is  drawn  from 
the  atmosphere.  This  consists  virtually  of  a  closed  cylinder 
with  a  number  of  very  narrow  longitudinal  slits  arranged 
usually  in  two  sections  as  shown,  and  by  this  means  the 
access  of  dust  is  prevented,  while  the  noise  due  to  the  rush 
of  the  incoming  air  is  reduced  to  a  minimum.  The  fuel 
valve  and  pulveriser,  B — perhaps  the  most  important 
detail  of  the  engine — is  fixed  directly  in  the  centre  of  the 


10. — Longitudinal  Section  of  M.A.N.  Diesel  Engine. 

[To  face  page  62. 


Fio.   IS.— 1  000  H.P.  Four-Cycle  Augsburg  Engin 


CONSTRUCTION   OF  THE   DIESEL   ENGINE        63 

cylinder,  and  is  likewise  contained  in  the  cylinder  head, 
the  needle  being  held  in  position  by  an  adjustable  spring. 
The  starting  valve  V  is  fixed  as  close  as  is  practicable  to 
the  fuel  valve,  and  is  of  somewhat  similar  type  in  this 
design  to  the  exhaust  and  suction  valves,  except  that  it 
is  much  smaller.  The  cam  shaft  H  is  supported  between 
two  bearings  on  brackets  bolted  to  the  cylinder  casting, 
one  of  these  brackets  being  seen  in  Fig  17.  This  shaft 
carries  the  four  cams  S  in  Fig.  17.  The  valve  levers  which 
are  actuated  by  the  several  cams  are  pivoted  on  a  spindle 
supported  by  two  small  standards  fixed  to  the  cylinder 
head,  the  starting  valve  cam  lever  D,  and  the  fuel  valve 
lever  F  being  seen  in  Fig.  1 7.  The  vertical  governor  spindle 
C  which  operates  the  cam  shaft,  the  fuel  valve  pump,  the 
governor,  and  in  some  machines  the  small  lubricating 
pumps,  is  driven  off  the  main  crank  shaft  by  a  worm 
drive,  running  in  oil  and  provided  with  a  coupling  near 
the  bed-plate  to  facilitate  removal  and  inspection.  The 
gear  box  contains  the  spur  wheels  through  which  rotation 
is  given  to  the  cam  shaft  at  half  the  speed  of  the  engine 
shaft.  The  governor  M  is  of  the  ordinary  type,  and  regu- 
lates the  speed  of  the  engine  by  controlling  the  amount  of 
fuel  admitted  to  the  cylinder  in  a  manner  described  later. 
The  cyhnder  liner  is  separate  from  the  main  casting,  both 
of  which  are  usually  of  cast  iron,  and  ample  space  is  left 
for  the  water  jacket,  the  coohng  water  entering  the 
bottom  of  the  cyhnder  and  leaving  at  the  top  of  the 
cyhnder  cover,  through  the  dehvery  pife  P.  In  some 
engines  the  exhaust  pipe  and  the  exhaust  valve  are  also 
water  jacketed,  this  adding  shghtly  to  the  efficiency  of 
the  machine.  It  is  essential  in  any  case  that  the  cover 
should  be  well  cooled,  in  order  to  prevent  the  valves  becom- 
ing overheated,  and  it  is  made  of  massive  construction, 
being  secured  to  the  cyhnder  by  eight  studs  of  ample  size. 
The  piston  is  usually  of  the  cast-iron  trunk  type,  shghtly 
dished  at  the  top,  and  is  particularly  long  in  order  to 
provide  a  good  bearing  surface  to  reduce  the  pressure  due 
to   the  obliquity  of  the  piston  rod.     It  is    always  fitted 


CONSTRUCTION   OF  THE   DIE8EL   ENGINE        65 

with  six  to  eight  Ramsbottom  rings  to  secure  tightness, 
and  lubrication  is  effected  through  a  small  pipe,  which 
communicates  with  the  cylinder  liner  near  the  centre,  and 
delivers  into  an  annular  space  in  it,  provided  with  a  number 
of  very  small  holes  piercing  the  liner  and  giving  access  of 
the  oil  to  the  piston.  The  connecting  rod  brasses  are  made 
adjustable  in  the  usual  way  to  take  up  wear,  and  are  well 
lubricated.  The  air  compressor  L  in  this  machine  is  driven 
off  the  connecting  rod  by  link  levers,  the  compressor  cylinder 
being  bolted  to  the  front  of  the  engine  cylinder,  though 
this  method  is  by  no  means  generally  adopted,  the  drive 
often  being  arranged  directly  off  the  crank  shaft  at  the  end 
of  the  machine  remote  from  the  flywheel,  with  the  cyhnders 
fixed  to  the  bed-plate.  The  compressor  shown  in  Figs.  16 
and  17  is  of  the  two-stage  type,  as  employed  for  small 
machines,  and  the  cylinder  is  also  water  cooled,  the  same 
water  being  used  as  for  the  engine  cylinder  jacket,  or  by- 
passed from  the  main  supply  as  may  be  desired.  The  com- 
pressed air  from  the  compressor  is  delivered  direct  into 
the  air  injection  blast  reservoir  through  copper  piping.  An 
illustration  of  two  M.A.N,  four-cycle  engines  is  shown  in 
Figs.  18  and  19,  the  first  being  of  1,000  H.P.  and  the  second 
of  880  H.P. 

Valves  and  Cams. — The  action  of  the  various  cams  may 
be  examined  at  this  point,  this  being  a  matter  of  importance, 
as  the  exact  time  of  the  opening  of  the  valves,  relative  to  the 
position  of  the  piston,  and  the  duration  of  this  opening  is 
controlled  entirely  by  the  cams  which  operate  the  valves 
through  intermediary  levers.  The  position  of  the  cams 
relative  to  each  other  is  thus  an  important  point,  and  is  best 
explained  by  a  diagrammatic  representation  of  them.  In 
Fig.  20  the  fuel  valve  cam  is  indicated  by  A,  the  exhaust  valve 
cam  by  B,  the  air  suction  valve  by  C,  and  the  starting  valve 
cam  by  D.  In  a  four-cycle  engine  each  valve  must  be  open 
once  in  two  revolutions,  and  the  cam  shaft  must  necessarily 
rotate  at  half  the  speed  of  the  crank  shaft.  In  the  diagrams, 
therefore,  one  revolution  of  the  crank  shaft  is  represented 
by  a  semicircle  or  180°,  while    during  one  stroke  of  the 

F 


66   DIESEL  ENGINES  FOR  LAND  AND  MARINE  WORK 

piston  each  cam  makes  a  quarter  of  a  revolution.  The  verti- 
cal and  horizontal  diameters  in  Fig.  20  therefore  represent 
top  and  bottom  dead  centres  of  the  crank,  the  vertical  lines 
being  taken  as  top  dead  centres  and  the  horizontal  ones  as 
the  bottom  dead  centres.  The  arrangement  of  the  cam  is 
now  easily  understood.  The  fuel  cam  opens  the  fuel  valve 
just  previous  to  the  piston  reaching  the  end  of  its  up  stroke, 
thus  giving  pre-admisson  to  the  extent  of  perhaps  1  per 
cent,  of  the  stroke  or  less,  depending  on  the  speed  of  the 
engine.     The  valve  is  then  held  open  for  the  required  period, 


Fuel  Vslve  Cam. 
A 


Exhaust    Valve  Cam.        Admission   Valve  Cam.    Starting  Valve  Cam. 
B  CD 


Fig.  20. — Diagram  showing  Arrangement  of  Cams 
with  Diesel  Engine. 


the  total  amount  of  the  opening  being  through  an  angle  of 
8  or  10  per  cent.  The  exhaust  valve  cam  similarly  opens 
slightly  before  the  end  of  the  working  stroke,  remains  open 
during  the  whole  of  the  next  or  exhaust  stroke,  and  closes 
just  after  the  top  dead  centre  is  reached.  Air  admission 
commences  through  the  air  suction  valve  just  before  the 
end  of  the  exhaust  stroke,  and  the  valve  is  kept  open  during 
the  next  stroke,  and  closes  immediately  after  the  crank 
passes  the  bottom  dead  centre.  The  starting  valve  cam  is 
arranged  to  open  the  valve  just  before  the  top  dead  centre 
is  reached,  and  to  close  it  some  considerable  time  before  the 
end  of  the  stroke.     All  the  cams  are  arranged  so  that  the 


CONSTRUCTION   OF  THE   DIESEL   ENGINE        67 

valve  opens  very  slightly  during  the  first  moment  of  contact 
of  the  cam  with  the  lever,  after  which  the  valve    opens 


Fig.   21. — Fuel  Inlet  Valve,  Lever  and  Cam. 


rapidly  to  its  full  extent,  and  closes  in  the  same  manner, 
so  that  in  the  actual  operation  a  very  quick  admission  and 


68   DIESEL  ENGINES  FOR  LAND  AND  MARINE  WORK 

cut  off  is  obtained.  The  diagram  does  not  show  the  cams 
in  their  actual  relative  positions,  as  if  this  were  so  all  the 
levers  would  have  to  be  arranged  parallel  with  each  other 
and  the  valves  open  in  the  same  direction  ;  usually,  in 
the  actual  engine,  the  exhaust,  air  suction,  and  starting 
valves  all  open  inwards  to  the  cylinder,  whilst  the  fuel 
inlet  valve  opens  outwards,  and  the  lever  actuating  it 
has  therefore  to  be  set  at  a  different  angle  from  the  other 
levers. 

The  general  arrangement  of  the  fuel  inlet  valve  with  the 
cam  and  lever  for  its  operation  is  shown  in  Fig.  21.  When 
the  nose  of  the  cam  comes  in  contact  with  the  valve  lever, 
this  is  forced  outwards  and  the  valve  is  opened  against 
the  pressure  of  a  spring,  which  normally  keeps  the  valve 
on  its  seat,  the  amount  of  the  opening  being  extremely  small. 
Fig.  21  also  shows  the  starting  handle  which  when  in  the 
horizontal  position  causes  the  starting  valve  lever  to  come 
in  contact  with  the  nose  of  its  cam  as  the  cam  shaft  rotates, 
while  the  fuel  valve  lever  is  held  clear  of  its  cam  at  the  same 
time.  When  the  starting  handle  is  in  the  vertical  position 
the  starting  valve  lever  is  clear  of  its  cam,  and  the 
fuel  valve  lever  then  comes  into  operation.  It  is  a  great 
convenience  if  the  lever  is  so  constructed  that  there  is 
a  joint  between  the  spindle  on  which  it  is  pivoted  and 
the  valve  spindle,  since  this  joint  can  then  readily  be 
broken  and  the  valve  easily  removed.  This  arrangement, 
though  not  universal,  is  now  adopted  by  a  large  number 
of  makers,  and  the  design  employed  by  Messrs.  vSulzer  Bros. 
is  shown  in  Fig.  25. 

Fig.  26  shows  a  detail  drawing,  partly  diagrammatic,  of 
the  type  of  fuel  inlet  valve  and  pulveriser  most  commonly 
emploj^ed  with  Diesel  engines,  though  there  are  slight  differ- 
ences vaih.  engines  of  various  makes.  The  oil  from  the  fuel 
pump  enters  through  the  pipe  A,  the  amount  being  regu- 
lated by  the  action  of  the  governor  on  the  pump  to  suit  the 
load  on  the  engine.  The  oil  flows  dowai  the  small  cylindrical 
hole  B  and  enters  the  annular  space  C  through  D  near  the 
bottom  of  the  needle  valve  E,  ground  to  an  angle  of  about 


[To  face  parje  ()8. 


Fig.  1>1>.— Detnik  of  Furl    Irih-t  \^iivc  (Carels  Tj^it.-). 


[To  face  paije  (iS. 


-^ 

CONSTRUCTION   OF  THE   DIESEL   ENGINE 


71 


30°,  just  above  the  pulverising  or  spraying  arrangement. 
For  this  purpose  there  are  four  metal  rings  F,  each  containing 
a  large  number  (twenty  or  more)  of  small  holes  usually  one- 
tenth  to  one-sixteenth  of  an  inch  in  diameter.  The  holes 
in  the  plates  or  rings  are  staggered  as  shown  in  the  figure, 
so  that  the  oil  may  not  be  blown  directly  through  them, 
and  between  the  plates  are  very  small  bands  G.     Below 


Fig.   25. — Jointed  Valve  Lever. 


the  rings  is  a  conically-shaped  piece,  in  the  periphery  of 
which  is  about  the  same  number  of  channels  as  there 
are  holes  in  the  rings,  and  these  channels,  which  may  be  from 
one-sixteenth  to  one-twentieth  of  an  inch  deep,  form  a 
series  of  nozzles,  through  which  the  fuel  has  to  pass,  after 
getting  through  the  holes  in  the  rings.  It  then  enters  the 
cylinder  by  the  expanding  orifice,  which  is  made  of  steel,  the 
guides  for  the  needle  valve  being  of  cast  iron.     The  annular 


72   DIESEL  ENGINES  FOR  LAND  AND  MARINE  WORK 

space  C  is  always  in  direct  connexion  with  the  injection 
air  reservoir  as  soon  as  the  valve  on  the  reservoir  is  opened, 
and  the  air  enters  the  space  near  the  top  through  another 
pipe  and  a  cylindrical  hole  in  the  same  casting  as  that  for  the 


Fig.    2(). — Fuel   Inlet   Valve  and  Pulveriser. 


fuel  inlet.  The  space  C  is  thus  always  subjected  to  the  high 
pressure  of  the  injection  air,  and  immediately  the  needle 
valve  lifts,  the  fuel  is  forced  through  the  pulveriser  by  the  air 
in  the  form  of  a  very  fine  spray,  and  combustion  at  once 


CONSTRUCTION   OF  THE   DIESEL  ENGINE        73 

takes    place.     A  small    cock  31  is  provided  having    con- 
nexion with  the  inlet  pipe  and  serves  the  purpose  of  a  test 


Fig.   27.— Details  of  Fuel  Inlet  Valve  of  Deutz  Engine. 


cock  and  an  overflow.  The  oil  may  be  pumped  up  by  hand 
before  starting  the  engine,  and  by  opening  the  cock  31  it  can 
be  seen  at  once  if  the  flow  of  oil  is  unmterruptcd.     The 


74   DIESEL  ENGINES  FOR  LAND  AND  MARINE  WORK 


/ 


Fig.   28. — Fuel  Inlet  Valve  oi  Aktiebolaget  Diesels  Motorer  T;y'pe. 

method  of  fixing  the  valve  guides  in  position,  and  the  ar- 
rangement of  the  stuffing  box,  will  be  understood  from  the 


CONSTRUCTION    OF  THE  DIESEL   ENGINE        75 

figure.  By  removing  the  valve  lever,  the  valve  can  readily 
be  taken  out  and  examined,  and  as  is  seen  in  Fig.  21,  the 
compression  of  the  spring  can  be  altered  as  required.  It 
might  be  expected  that  different  pulverisers  would  be 
required  when  different  fuels  are  employed,  but  as  a  matter 
of  fact  it  is  found  that  the  same  pulveriser  will  operate  quite 
satisfactorily  for  grades  of  fuel  of  very  different  viscosity, 
and  they  are  constructed  to  be  suitable  for  the  thickest  oils. 


Fig.    29. — Moiitlipiece  or  Battum   fart  of   i'uheriser. 

and  no  trouble  is  then  experienced  with  less  viscous  fuels. 
The  type  of  pulveriser  and  fuel  inlet  valve  adopted  by 
the  A.  B.  Diesels  Motorer  of  Stockholm  dift'ers  somewhat 
from  the  usual  construction,  and  is  said  to  give  ver}^  efficient 
results.  This  is  illustrated  in  Figs.  28  and  29,  and  the  method 
of  operation  is  shown  in  Fig.  30.  The  oil  enters  the  annular 
space  at  the  bottom  from  the  fuel  pumps  in  the  usual  way, 
position  1   {Fig.  30)  showing  the  amount  left  immediately 


76   DIESEL  ENGINES  FOR  LAND  AND  MARINE  WORK 

after  the  injection  into  the  cylinder.  In  position  2  the  oil 
has  been  pumped  up  from  the  fuel  pump,  while  in  position  3 
the  fuel  valve  has  lifted,  and  the  oil  is  being  injected  into 
the  cylinder.  The  blast  of  air  forces  the  oil  through  specially 
shaped  passages,  which  are  usually  curved,  or  of  Lregular 
form,  and  the  mixture  is  given  a  spiral  motion,  the  heavier 
particles  of  oil  being  throw  n  against  the  sides  of  the  passage 
so  that  complete  pulverisation  takes  place.  The  pulveriser 
is  entirely  cleared  of  oil  with  each  injection,  w'hich  in  rever- 
sible marine  engines  is  a  considerable  advantage,  and  it 


(2)  (3) 

Fig.   30. — Diagram  sliowiiiK  Action  nf  Pulveriser. 


necessitates  that  the  exact  amount  of  oil  delivered  by  the 
pump  is  injected  into  the  working  cylinder. 

The  general  arrangement  with  the  ordinary  type  of  Diesel 
engine  of  the  fuel  valve,  exhaust  and  air  suction  valves  in 
the  cylinder  cover  is  shown  in  Fig.  31 ,  while  Fig.  33  gives  a 
section  through  the  exhaust  valve  and  cam  shaft  showdng 
the  operation  of  the  valve.  It  will  be  noticed  from  the 
illustrations  that  the  removal  of  the  valves  can  be  carried 
out  very  expeditiously  in  all  cases.  In  some  engines,  not- 
ably those  constructed  in  America,  the  fuel  inlet  valve  is 
arranged  horizontally  on  the  side  of  the  cylinder  head,  w^hich 
projects  well  over  the  cylinder,  and  the  exhaust  valve  and 


CONSTRUCTION   OF  THE   DIESEL   ENGINE 


77 


admission  valve  are  also  fitted  into  this  projection,  the 
exhaust  valve  in  the  top  and  the  admission  valve  under- 
neath. 

Regulation  of  the  Engine. —  The  same  method  of  govern- 
ing the  speed  of  Diesel  engines  of  the  land  type  with  varying 


Fig.   31. — Air  Inlet  and  Exhaust  Valves  (in  section). 


load  is  adopted  by  practically  all  the  chief  manufacturers, 
there  being  naturally  some  differences  in  constructional 
detail.  The  control  is  effected  entirely  by  regulation  of  the 
amount  of  oil  admitted  into  the  cylinder  through  the  fuel 
inlet  valve,  and  hence  no  alteration  in  the  stroke  or  the  dura- 


fe 


CONSTRUCTION   OF  THE   DIESEL   ENGINE        79 

tion  of  the  opening  of  this  valve  is  required,  which  would  be 
the  necessary  means  of  governing  if  the  fuel  supply  were  not 
varied  ;  the  latter  method  is  obviously  more  convenient 
from  many  points  of  view,  particularly  inasmuch  as    the 


Fig.   33. — Exhaiist  Valve  (section). 


valves  may  be  set  and  never  touched  once  the  engine  has 
been  put  to  work.  A  small  fuel  pump  is  provided  which 
pumps  the  oil  to  the  fuel  valve  through  a  connecting  delivery 
pipe.     The  oil  is  drawn  into  the  pump  cylinder  on  the  up 


80    DIESEL  ENGINES  FOR  LAND  AND  MARINE  WORK 


%  b'    'I 

Fig.  34. — Arrangement  of  Governor  and  Fuel  Valve  of  Mirrlees,  Bickerton 

&  Day  Type. 


stroke  of  the  pump  plunger,  through  a  small  valve,  and 
on  the  down  stroke  this  valve  remains  open  for  a  short  period, 
after  which  all  the  oil  is  pumped  into  the  cylinder.     The 


CONSTRUCTION   OF   THE   DIESEL   ENGINE        81 

period  during  which  the  suction  valve  remains  open  in 
the  down  stroke  of  the  phniger  of  the  pump,  is  controlled 
by  the  governor,  so  that  if  the  speed  rises  too  high  the  suction 
valve  is  held  open  for  a  longer  time,  and  less  oil  is  delivered 
to  the  engine  cylinder,  whereas  if  the  speed  is  low  the  suction 
valve  closes  almost  immediately  at  the  beginning  of  the 
down  stroke  of  the  plunger,  and  most  of  the  oil  drawn  in 
during  the  suction  stroke  is  pumped  into  the  cylinder  dur- 
ing the  delivery  stroke.  In  multi-cylinder  engines  some 
makers  prefer  to  have  a  separate  fuel  pump  for  each  cylin- 
der, whilst  others  employ  only  one  pump  for  supplying  all 
the  cylinders,  though  this  is  perhaps  on  the  whole  not  quite 
so  satisfactory,  but  is,  of  course,  simpler. 

Fig.  34  shows  diagrammatically  the  arrangement  adopted 
by  Messrs.  Mirrlees,  Bickcrton  &  Day,  Ltd.,  for  governing 
the  supply  of  fuel  to  the  cylinder.  A  is  the  plunger  of  the 
fuel  pump,  which  obtains  its  motion  from  an  eccentric  on 
the  cam  shaft  or  vertical  intermediate  shaft  of  the  engine. 
On  the  up  stroke  of  the  plunger,  oil  is  drawn  in  through  the 
suction  valve  C ,  which  is  opened  by  the  motion  of  the  rod 
D,  attached  to  a  link  in  the  crosshead  of  the  fuel  pump.  The 
action  of  the  suction  valve  is  more  clearly  seen  in  the  illus- 
tration to  the  left  of  Fig.  34,  the  oil  being  drawn  from  the 
chamber  E  in  the  direction  of  the  arrows.  During  the 
down  stroke  of  the  plunger  the  oil  which  has  been  dra^n  in 
is  forced  up  through  the  fuel  delivery  pipe  to  the  fuel  inlet 
valve  so  long  as  the  suction  valve  remains  closed,  but  while 
this  latter  is  open  no  oil  can  be  delivered,  all  being  forced 
back  into  the  chamber  E.  The  action  of  the  pump  can  now 
be  explained  in  relation  to  the  governor  F,  which  is  of  the 
Hartnell  type.  When  the  speed  of  the  engine  rises,  the 
governor  balls  or  weights  spring  outwards  to  the  positions 
as  indicated  by  the  centre  lines,  and  by  means  of  the  link 
mechanism  shown,  the  rod  D,  actuating  the  suction  valve, 
is  raised  till  the  centre  of  the  pin  on  which  the  lever  G 
turns,  reaches  the  level  c/,and  the  stroke  of  D  is  then  a  b 
instead  of  a'b'  when  the  governor  balls  are  "in."  The 
suction  valve  is  thus  held  open  for  a  longer  period  of  the 

G 


82   DIESEL  ENGINES  FOR  LAND  AND  MARINE  WORK 

down  stroke  of  the  plunger  ^,  and  less  oil  is  therefore  de- 
livered to  the  engine  cylinder,  and  the  speed  drops,  when  the 
governor  balls  move  inwards  and  the  lever  6-' returns  to  its 
normal  stroke. 

In  the  type  of  fuel  pump  employed  by  the  Maschinen- 
fabrik  Augsbiirg-Niirnberg,  the  pump  plunger  is  actuated 


Fig.   35.— Fuel  Pump  (Willans  &  Robinson  Type). 


by  an  eccentric  on  the  motion  shaft  as  before,  and  the  suc- 
tion vajve  is  opened  by  a  finger  piece  attached  to  a  vertical 
lever,  which  derives  its  up  and  down  motion  from  another 
lever  attached  to  the  pump  rod  and  pivoted  eccentrically 
to  the  spindle  driving  it.  The  spindle  has  a  small  crank 
fixed  to  it,  to  which  is  attached  a  vertical  rod,  actuated  by 


CONSTRUCTION   OF   THE   DIESEL  ENGINE        83 

the  governor  mechanism,  and  when  the  speed  of  the  engine 
falls  so  that  the  governor  balls  move  inwards,  this  rod  is 
depressed,  and  the  small  crank  turned  through  an  angle,  thus 
causing  the  rod  operating  the  suction  valve  to  hold  it  open 
for  a  shorter  period  than  the  normal.  More  oil  is  then 
delivered  to  the  fuel  inlet  valve  and  the  engine  speed  rises. 

The  level  of  the  oil  in  the  oil  chamber  is  maintained  con- 
stant by  a  float,  and  a  pipe  from  this  chamber  is  connected 
directly  with  the  supply  from  the  fuel  filters.  The  fuel  pump 
casing  is  usually  fixed  to  the  cylinder  about  the  middle,  and 
the  plunger  has  a  vertical  motion  from  the  eccentric  on  the 
horizontal  cam  shaft,  while  the  governor  lever  is  attached  to 
the  governor  sleeve  on  the  vertical  governor  shaft  of  the 
engine. 

Fig.  35  shows  the  design  of  fuel  pump  and  governor 
adopted  by  Messrs.  Willans  &  Robinson,  Ltd.,  for  their 
standard  engines,  this  being  of  the  horizontal  type.  The 
vertical  governor  shaft  a,  which  also  drives  the  cam  shaft 
through  bevel  gearing,  is  driven  off  the  crank  shaft  of  the 
engine  by  worm  gearing,  and  has  fixed  to  it  the  governor 
casing.  The  governor  consists  of  weights  attached  to  a 
central  sleeve,  the  effect  being  that  any  outward  or  inward 
motion  of  the  weights  due  to  variation  of  speed  of  the  engine, 
causes  an  angular  motion  to  the  loose  sleeve,  carrying  the 
eccentric  h  which  operates  the  small  rod  c.  The  movement 
of  this  rod  gives  an  angular  motion  to  the  crank  piece  d, 
which  in  turn  raises  the  oil  suction  valve  e  off  its  seat  and 
admits  oil  from  the  chamber  /  into  the  plunger  cylinder  g, 
the  plunger  itself  being  driven  from  an  eccentric  Jix  on  the 
governor  shaft.  The  fuel  inlet  from  the  filters  is  seen  at  /. 
On  the  outward  stroke  of  the  plunger  if  the  suction  valve  is 
closed,  the  oil  is  delivered  past  the  valve  h,  which  is  opened 
against  a  spring,  and  the  oil  flows  through  the  outlet  pipe 
to  the  fuel  inlet  valve  of  the  engine  cylinder.  The  action 
of  the  governor,  except  for  its  mechanism,  is  similar  to  that 
already  described.  If  the  engine  speed  rises  and  the  weights 
move  outwards  the  sleeve  carrying  the  suction  valve  rod 
eccentric  is  turned  through  a  smaU  angle.     The  stroke  of  the 


84   DIESEL  ENGINES  FOR  LAND  AND  MARINE  WORK 

rod  is  then  such  as  to  keep  the  suction  valve  open  during  a 
greater  portion  of  the  outward  stroke  of  the  plunger,  so  that 
less  oil  is  delivered  through  the  outlet  pipe,  and  hence  the 
speed  of  the  engine  falls,  and  the  eccentric  regains  its  normal 
position.  The  spindle  j)  may  be  turned  by  hand,  and  this 
allows  for  three  positions  of  the  spindle.  In  the  normal  or 
running  position  both  the  suction  and  delivery  valves 
are  quite  free  ;  in  the  second  position  the  suction  valve  is 
closed,  the  fuel  supply  thus  being  cut  off  from  the  engine, 
which  must  then  stop,  while  in  the  third  position  the  suction 
valve  still  remains  closed  and  the  delivery  valve  is  opened,  so 
that  any  oil  in  the  pipes  between  the  pump  and  the  fuel  inlet 
valve  runs  back  into  the  plunger  cylinder.  By  this  means 
the  oil  is  prevented  from  being  pumped  in  excess  in  the  fuel 
chamber  at  starting,  and  if  a  separate  fuel  pump  be  provided 
with  each  cylinder,  one  cylinder  may  be  readily  cut  out  of 
operation.  The  pressure  on  the  governor  springs  may  be 
altered  by  means  of  the  arrangement  shown,  and  hence  the 
running  speed  of  the  engine  can  be  varied  within  reasonable 
limits. 

It  is  not  usual,  in  the  smaller  sizes  of  Diesel  engines,  to 
employ  any  other  form  of  governing  other  than  by  altering 
the  amount  of  fuel  injected  into  the  cylinders,  according 
to  the  load,  by  means  of  one  of  the  methods  previously 
described.  In  the  larger  engines,  it  is  desirable  for  the 
amount  of  injection  air  to  be  independently  controlled, 
and  also  the  period  of  admission  for  the  fuel  and  air,  which 
is  not  generally  arranged  for  in  stationary  motors. 

This  is,  however,  accomplished  in  one  of  the  designs  of 
Messrs.  Sulzer,  as  illustrated  in  Fig.  36,  and  it  is  useful 
for  engines  which  have  to  be  run  in  parallel  with  steam 
engines,  gas  engines  or  water  turbines,  and  where  there 
are  sudden  and  substantial  variations  of  load.  Referring 
to  the  illustration,  the  governor  r  influences,  according  to 
its  position,  all  the  factors  on  which  the  desired  output 
depends,  i.e.,  the  quantity  of  fuel  injected,  the  volume  and 
pressure  of  the  air  necessary  for  injecting  and  pulverizing 
the  fuel,  as  well  as  the  period  of  admission  of  the  fuel  valve, 


Flu.  37.— Front  Elevation  nf  Mirrlecs  Diesel  Engir 


CONSTRUCTIOX   DF  THE  BIE.SEL  ENGINE        85 


in  accordance  with  the  quantities  of  air  and  fuel.  The 
quantity  of  the  fuel  and  the  volume  and  pressure  of  injec- 
tion air  are  adjusted  from  the  governor  by  direct  action, 
since  the  power  for  carrying  out  the  movements  is  small. 
The  quantity  of  injection  air  dejDends  on  the  position  of 
the  piston  valve  d.  which  is  inserted  in  the  suction  pipe  of 
the  first  stage  of  the  injection  air  pump.  The  control  of 
the  admission  period  of  the  fuel  valve,  however,  requires 
some  effort,  owing  to  the  re- 
sistance of  the  valves,  which 
cannot  conveniently  be  exer- 
cised by  the  governor  direct. 
For  this  purpose,  a  small  servo- 
motor S  is  employed,  which  is 
operated  b}^  the  variation  of 
pressure  effected  in  any  stage 
of  the  injection  air  pump. 
Referring  to  the  illustration, 
the  pressure  existing  between 
the  first  stage  /  and  the  second 
stage  k  of  the  injection  pump 
is  used  for  the  purpose,  the 
servo-motor  bemg  connected 
by  the  pipe  u. 

Types  of  Four-Cycle  En- 
gine.— Figs.  37  and  38  show 
vertical  front  and  side  sectional 
elevations  of  the  standard 
Diesel  engine  constructed  by 
Messrs.  Mirrlees,   Bickerton   & 

Day,  Ltd.  The  usual  long  piston  is  employed,  and  the  head 
is  slightly  dished  and  ribbed  to  add  to  its  strength.  The 
weight,  however,  of  the  piston  is  not  excessive,  as  its  thick- 
ness is  considerably  reduced  below  the  gudgeon  pin,  which 
is  hollow  and  is  fixed  to  the  piston  by  two  studs  screwed  in 
from  below.  The  big  and  small  end  bearings  are  lined  with 
white  metal,  and  the  former  is  of  the  box  type,  and  has  dis- 
tance pieces  in  it  so  that  the  length  of  the  connecting  rod 


Fig.  36. — Arrangement  for  eon- 
trolling  Fuel  and  Injection  Air. 


8G     DIESEL  ENGINES  FOR  LAND  AND  MARINE  WORK 

may  be  varied,  which  besides  taking  up  wear  allows  for 
variation  of  the  clearance  between  the  piston  and  cylinder, 


and  hence  is  useful  for  varying  the  compression  of  the  engine. 
A  two  stage  vertical  air  compressor  is  used,  driven  direct  off 


Section  of  80  H.P.  Engine. 

[To  face  paijc  87. 


^ 


CONSTRUCTION  OF  THE  DIESEL  ENGINE        87 

the  end  of  the  crank  shaft,  the  high  pressure  cyhnder  being 
directly  above  the  low  pressure,  and  an  intercooler  for 
reducing  the  temperature  of  the  air  between  the  two  stages 
is  provided. 

A  longitudinal  and  transverse  section  of  the  standard  slow 
speed  type  of  single  cylinder  engine,  manufactured  by  the 
Nederlandsche  Fabriek  of  Amsterdam,  are  given  in  Fig.^^. 
4,0  and  ^\  respectively.  The  general  arrangement  does  not 
differ  in  any  marked  degree  from  the  designs  already  de- 
scribed, except  that  the  air  pump  for  the  injection  and  start- 
ing air  is  mounted  on  the  end  of  the  engine  on  an  extension 
of  the  bed-plate,  and  is  driven  by  an  overhung  crank,  the 
compressor  being  of  the  two  stage  type  with  intercooling 
between  the  stages.  The  piston  is  of  the  trunk  type,  made 
of  high-grade  cast  iron,  as  is  also  the  cylinder  liner,  a  special 
mixture  as  usual  being  employed  for  the  cylinder  head,  in 
view  of  the  high  pressures  to  which  it  is  subjected.  A  small 
lubricating  pump  and  oil  reservoir  are  provided  in  the  com- 
pressor end  of  the  engine,  seen  in  Fig.  40  and  also  in  Fig.  42, 
which  is  a  plan  of  the  engine,  and  shows  the  general  arrange- 
ment of  the  valves  in  the  cylinder  head,  and  the  cam  shaft, 
cams  and  valve  levers  operating  them.  The  cam  shaft  is 
driven  in  the  usual  way  at  half  the  speed  of  the  engine,  by 
means  of  spur  gearing  through  a  vertical  spindle,  itself 
driven  off  the  crank  shaft  by  a  worm  drive.  Fig.  43  shows 
the  air  inlet  valve  with  its  cam  and  valve  lever,  and  also  the 
by-pass  through  which  the  cooling  water  passes  from  the 
cylinder  jacket  to  the  cylinder  head.  In  Fig.  44  a  de- 
tailed section  is  given  of  the  governor  and  fuel  pump  in 
their  relation  to  the  overhead  cam-shaft.  The  prin- 
ciple of  the  action  of  the  fuel  pump  and  the  regulation 
of  the  speed  of  the  engine  is  the  same  as  that  generally 
adopted  with  Diesel  engines — namely,  the  control  of  the 
period  of  opening  of  the  suction  valve  of  the  fuel  pump.  If 
owing  to  increase  of  speed  the  governor  balls  spring  outwards, 
the  governor  sleeve,  to  which  the  pivoted  arms  carrying  the 
balls  are  attached,  is  lowered,  carrying  with  it  the  horizontal 
lever  seen  in  the  illustrations.     This  lever  is  attached  at  one 


88    DIESEL  ENGINES  FOR  LAND  AND  MARLNE  WORK 


i 
Fig.  42.— rian  of  80  H.P.   Ensine. 


1 


end  to  a  piston  moving  in  a  dash  pot  to  prevent  too  rapid 
motion,  and  at  the  other  end  is  connected  by  a  short  Hnk 
to  the  rod  controlling  the  opening  of  the  suction  inlet  valve 
of  the  fuel  pump.  The  plunger  of  the  pump  is  driven  by  an 
eccentric  off  the  vertical  governor  shaft,  and  this  eccentric 
by  means  of  a  link  attached  to  the  eccentric  rod,  also  gives 


CONSTRUCTION   OF  THE  DIESEL  ENGINE 


a  regular  oscillating  motion  to  the  suction  valve  operating 
rod  previously  mentioned  and  so  opens  and  closes  the  valve. 
When  the  horizontal  lever  on  the  governor  sleeve  is  depressed 
by  the  opening  out  of  the  governor  balls  due  to  the  increased 
engine  speed,  the  link  connecting  it  to  the  suction  valve 
operating  rod  becomes  straightened  out,  and  it  is  moved  to 
the  right  so  that  the  period  of  opening  of  the  suction  valve 
during  the  forward  stroke  of  the  plunger  is  increased  ;  less 
oil  is  consequently  delivered  through  the  outlet  valve  of  the 
pump  to  the 
fuel  inlet 
valve  of  the 
engine,  a  n  d 
the  speed  of 
the  motor 
falls  until  it 
reaches  the 
normal,  when 
the  governor 
resumes  its 
o  r  dinar y 
running  posi- 
tion. 

In  this  en- 
gine a  safety 
valve  is  fitted 
in  the  cylin- 
der   head  to 

prevent  danger  arising  through  any  excess  of  pressure  in 
the  cylinder,  and  this  valve  may  be  operated  b}-  hand,  by 
the  lever  seen  in  Fig.  43  and  in  the  plan  view  Fig.  42.  All 
the  valves  are  provided  with  inserted  cages  for  ease  in  remov- 
ing, while  the  jackets  have  large  mud  holes  for  purposes  of 
cleaning,  which  is  frecfuently  of  great  advantage  where 
engines  are  cooled  with  dirty  water,  as  is  occasionally 
necessary. 

With  the  ordinary  type  of  Diesel  engine,  the  piston  has 
to  be  taken  out  from  the  top,  which  necessitates  removing 


43. — Arrangement  of  Air  Inlet. 


90      DIESEL  ENGINES  FOR  LAND  AND  MARINE  WORK 


Fig.   44. — Section  of  Fuel  Pump. 


all  the  valve  levers  and  lifting  the  cylinder  top.     In  the  more 
recent  construction  of  the  engines  of  the  Nederlandsche 


^^^^Xrrangement  of  Carels  Four-Stroke  Stationary  Motor, 
1 1  (irizontal  Three-Stage  Compressor. 


[To  face  page  90. 


Fig.  45.— General  Arningernent  of  Carols  Four-Stroke  Stationary  Motor, 
with  Horizontal  Throe-Stogo  Compn 


CONSTRUCTION   OF  THE   DIESEL   ENGINE 


91 


Fig.  4G. — Method  of  removing  Piston  in  Nederlandselie  Fabriek  Engine. 

Fabriek,  an  arrangement  has  been  adopted  by  means  of 
which  the  piston  can  be  taken  out  from  the  bottom  without 
interfering  with  the  valves  at  all.  This  is  illustrated  in  Fig. 
46  and  is  applicable  to  the  type  of  motor  in  which  the  trunk 
piston  is  adopted.  The  bottom  half  of  the  cylinder  consists 
of  an  extended  liner  bolted  on  the  upper  half,  and  when  the 
piston  is  lowered  and  the  portion  a  of  the  liner  removed,  it 
can  be  swung  forward  in  the  manner  sho^\•ll.     Fig.  47  shows 


92      DIESEL  ENGINES  FOR  LAND  AND  MARINE  WORK 


Fio.  4!).  — 7011  H.P.  Slow  Speed  Dieeel  Engine,  C'arels  Typo. 


I7V/UCT  imjc  03. 


CONSTRUCTION   OF  THE   DIESEL  ENGINE        93 

the  latest  design  of  three  cyHnder  stationary  engine  adopted 
by  this  firm,  in  which  a  connecting  rod  and  crosshead  are 
employed,  the  same  arrangement  of  removable  extended 
liner  being  used.  In  this  engine  there  is  a  two-stage  vertical 
compressor  mounted  on  the  end  of  the  bed-plate  in  line 
with  the  working  cylinders,  and  driven  direct  of!  the  crank 
shaft. 

In  Fig.  49  a  dimensioned  drawing  is  given  of  a  four-cylin- 
der four-cycle  slow  speed  engine  of  Messrs.  Carels"  construc- 
tion. The  motor  illustrated  is  one  of  700  B.H.P.,  running 
at  150  r.p.m. ,  arranged  for  dynamo  driving,  with  a  generator 
in  the  centre  and  two  cylinders  on  each  side.  Two  air 
compressors  of  the  Reavell  type  are  provided —  one  at  each 
end.  The  diameter  of  the  cylinders  is  570  mm.  and  the 
stroke  780  mm.,  and  even  for  this  relatively  high  power  the 
trunk  piston  is  retained. 

High  Speed  Engines.^ — As  has  been  explained  in  C  hapter 
II,  there  are  certain  advantages  attaching  to  engines  of  the 
high  speed  type,  and  for  special  purposes  they  will  probably 
be  widely  adopted  in  the  future.  The  high  speed  machine 
is,  of  course,  eminently  adapted  for  direct  driving  of  dyna- 
mos, and  though  it  is  hardly  probable  that  it  will  come  into 
general  use  for  this  purpose,  its  employment  for  many 
purposes  is  likely  to  be  very  extensive,  since  saving  in 
weight  and  space  is  often  of  great  importance,  while  the 
reduced  cost  of  installation  is  always  a  point  to  be  con- 
sidered. As  a  matter  of  fact,  high  speed  Diesel  engines 
direct  coupled  to  dynamos  have  for  some  time  past  been 
installed  on  battleships.  Some  details  of  the  size,  power 
and  speed  of  high  speed  engines  are  given  in  Chapter  W , 
but  in  many  cases  these  speeds  are  exceeded,  and  engines  of 
300  H.P.  running  at  400  revolutions  per  minute  are  common, 
while  the  type  constructed  by  Messrs.  Mirrlees,  Bickerton 
&  Day,  Ltd.,  for  British  battleships  consisting  of  a  120  H.P. 
engine  coupled  to  the  dynamo  runs  at  400  revolutions  per 
minute.  With  larger  powers  the  same  speed  of  rotation  is 
employed,  being  about  double  that  of  the  ordinary  land 
type. 


94    DIESEL  ENGINES  FOR  LAND  AND  MARINE  WORK 

The  high  speed  types  of  engine  built  by  this  firm  is  made  in 
the  following  sizes,  all  at  400  revolutions  per  minute  : — 


3  Cylinder 

engine. 

45  B.H.P 

3 

90 

4 

120 

6 

180 

6 

240 

6 

300 

The  chief  feature  of  the  construction  of  the  high  speed 
engine  lies  in  the  fact  that  practically  all  the  moving  parts 
are  totally  enclosed,  and  very  efficient  splash  lubrication  is 
effected,  and  a  smooth  operation  of  the  machine  is  obtained. 
The  bed-plate  is  usually  of  the  flat-bottomed  box  pattern  and 
has  bolted  on  to  it  the  crank  casing,  which  is  totally  enclosed 
and  provided  with  as  many  inspection  covers  on  each  side 
as  there  are  cranks.  All  the  outer  cylinder  walls  are  bolted 
on  to  the  crank  casing,  instead  of  being  cast  in  one  A\ith  the 
framing  as  is  the  case  with  low  speed  engines. 

In  Figs.  51  to  56  inclusive  are  given  drawings  of  high 
speed  engines  built  by  various  firms,  from  which  it  will  be 
seen  that  there  is  not  any  very  marked  difference  between 
the  several  types.  In  each  case  they  are  totally  enclosed 
and  provided  throughout  with  forced  lubrication,  which  is 
of  course  an  essential  feature  in  motors  running  at  rela- 
tively high  speed.  It  should,  however,  be  pointed  out  an 
engine  rotating  at  say  350  revolutions  per  minute  does  not 
necessarily  imply  that  the  piston  speed  is  correspondingly 
in  excess  of  that  in  the  slow  running  type,  for  the  difference 
is  in  fact  not  usually  very  great.  It  follows  from  this  that 
a  larger  number  of  cylinders  is  usually  adopted  for  the  same 
power  in  a  high  speed  engine,  whilst  the  ratio  of  stroke  to 
bore  is  much  diminished,  being  usually  in  the  neighbour- 
hood of  unity  or  slightly  over.  This  does  not  give  the 
maximum  efficiency,  but  in  cases  where  it  is  desirable  to 
employ  the  high  speed  engine  its  advantages  are  usually 


Fig.  48.— End   Section  of  (JOO  B.H.P.  Four-Cycle  Engine. 
95 


96      DIESEL  ENGINES  FOR  LAND  AND  MARINE  WORK 

such  as  to  counterbalance  any  slight  increase  in  fuel  con- 
sumption. 

The  large  high  speed  type  of  engine  manufactured  by  the 
Nederlandsche  Fabriek  offers  some  important  points  of 
difference  from  that  of  the  usual  construction.  Fig.  50 
shows  a  front  section  of  a  600  B.H.P.  engine  built  by  this 
firm,  to  run  at  215  revolutions  per  minute.  It  is  of  the 
usual  four-stroke  type,  with  four  cylinders,  the  two  inner 
having  the  cranks  set  at  180°  with  the  outer  pair.  A 
single  air  pump  is  employed,  mounted  on  the  end  of  the 
bed- plate,  being  of  the  vertical  two  stage  type,  and  driven 
direct  ofr  the  crank  shaft.  A  trunk  piston  is  not  used, 
but  there  is  a  crosshead  and  a  short  connecting  rod,  and 
though  the  length  of  the  piston  is  diminished,  since  it  no 
longer  has  to  be  of  the  usual  bearing  surface,  the  engine  is 
necessarily  somewhat  higher  than  the  ordinary  trunk  piston 
type.  The  crosshead  has  two  bearing  surfaces,  and  the 
guides  are  bolted  on  to  the  engine  framing,  and  a  forked  con- 
necting rod  end  is  employed,  as  shown  in  the  illustration. 
All  the  main  bearings  are  water-cooled,  as  is  also  the  piston, 
which  is  an  unusual  feature  in  a  four-cycle  engine,  cooling 
with  this  type  of  engine  usually  being  adopted  for  cylinders 
of  more  than  100  H.P.  The  arrangement  for  the  piston 
cooling  is  clearly  indicated  in  Fig.  50.  The  piston  rod 
itself  is  hollow  and  is  secured  to  the  piston,  which  is  also 
hollow,  through  a  flange  wrought  on  the  piston  rod,  fixing 
studs  being  arranged  in  the  piston  body.  Two  small  pipes 
are  connected  to  the  water  spaces  in  the  piston,  and  these 
slide  up  and  down  within  two  long  tubes  which  are  connected 
with  the  supply  and  delivery  pipes  for  the  cooling  water. 
Both  these  tubes  are  of  course  provided  with  stuffing  boxes, 
and  although  the  water  is  under  slight  pressure  no  leak- 
age takes  place.  The  water  outlet  for  the  cooling  water 
for  the  crank  shaft  bearings  delivers  into  a  cup  in  front 
of  the  engine  at  the  bottom,  and  as  there  is  a  separate  cup 
for  each  bearing  there  is  no  occasion  for  trouble  with 
any  of  the  bearings,  since  the  temperature  can  be  readily 
ascertained  and  varied  as  required.     Forced  lubrication  is 


{To  face  -page  90. 


Fig.  50.— Fruiit  Section  of  COO  B.H.P.  High  Speed  Eiigii 


[To  face  pcKjc  90 


Fig.  51.-21)0  H.P.  Sulzer  High-Speed 
FouT-CycIe  Stationary  Engine. 


[To  Jacc  pugc  90 


[To  face  page  9G. 


Fig.   52. — General  arrangement  plans  of  Twa-Cylinder  Hick.  Hnrgrej 
Motor.   10  in.  dinm..    1!)  in.  ttroke.     Speeil  250  r.|j.ni. 


[To  fate  paijr  90. 


CONSTRUCTION   OF  THE   DIESEL   ENGINE        97 

adopted  for  all  the  main  shaft  bearings,  as  well  as  for  the 
connecting  rod  bearings,  and  these  latter  are  very  accessible 

—  more  so,  of  course,  than  in  engines  in  which  a  trunk 
piston  is  employed. 

The  engine  is  constructed  with  a  box  frame,  the  cylinders 
which  are  cast  together  being  supported  directly  on  the 
frame,  while  further  strength  is  given  by  means  of  long  verti- 
cal bolts  which  attach  the  cylinders  rigidly  to  the  bed-plate. 
With  a  four-cylinder  engine  there  are  ten  of  these    bolts 

—  five  at  the  front  and  five  at  the  back.  The  crank 
chamber  is  entirely  enclosed,  a  hinged  door  being  provided 
in  front  of  each  connecting  rod,  and  the  piston  rods  pass 
through  the  stuffing  boxes  in  the  box  frame,  so  that  the 
connecting  rod  small  end  bearing  is  in  a  cool  atmosphere 
away  from  the  heat  of  the  cylinder. 

One  of  the  main  variations  in  construction  from  the  ordin- 
ary engine  is  the  use  of  eccentrics  for  operating  the  valve 
levers  instead  of  the  cams,  which  are  so  commonly  employed, 
the  object  being  to  diminish  noise  and  increase  the  smooth- 
ness of  running.     The  engine  is  constructed  with  a  horizontal 
cam  shaft  driven  in  the  usual  way  off  the  main  crank  shaft, 
but  in  place  of  cams,  it  has  fixed  on  to  it  eccentrics.     The 
eccentric  rods  are  attached  at  the  ends  to  horizontal  levers 
pivoted  eccentrically  on   a  horizontal  spindle,   and  these 
levers  thus  receive  an  up  and  down  motion.      At  the  oppo- 
site end  to  that  at  which  they  are  connected  to  the  eccentric 
rods,  the  valve  rods  operating  the  valves  rest  upon  them, 
and  hence  the  motion  of  the  eccentric  is  transmitted  to  the 
valves,  which   open  in  the   usual  way.     For  the  starting 
valve,  which  of    course  is  only    in  operation    for  a    few 
seconds,  the  ordinary  cam  and  valve  lever  are  employed. 
The    governor    is    arranged    on    the    vertical   shaft   driv- 
ing  the   horizontal  eccentric    spindle,    and    regulates    the 
speed  of  the  engine  by    controlling    the    duration    of   the 
opening  of  the  suction    valve    of  the   fuel    pump    during 
the  delivery   stroke,   and  thus  regulating  the  amount  of 
oil  admitted  to  the  cyhnder.     The    construction    of    the 
pump    and    governor    is    similar   to    that   described   pre- 

H 


98      DIESEL  ENGINES  FOR  LAND  AND  MARINE  WORK 

viously,  and  four  fuel  pumps  are  used  with  a  single  pump 
chamber. 

Engines  of  this  type  are  hardly  high  speed  in  the  ordinary 
sense,  inasmuch  as  they  run  only  about  30  per  cent,  faster 
than  the  usual  stationary  engine.  They  are  standardized 
from  about  200  B.H.P.  up  to  1,000  B.H.P.  with  speeds 
varying  between  275  and  200  revolutions  per  minute. 
Under  300  H.P.  the  engines  are  made  frequently  of  the 
three-cylinder  type,  but  above  that  power,  and  sometimes 
below,  four  cyhnders  are  always  used.  The  weight  per 
B.H.P.  is  remarkably  constant  for  all  sizes,  being  some- 
where in  the  neighbourhood  of  280  lb.  per  B.H.P.  including 
all  accessories.  The  approximate  overall  dimensions  of 
the  engine  illustrated  are  6  ft.  8  in.  by  27  ft.  6  in.  floor  space 
and  12  ft.  6  in.  in  height. 

The  high  speed  engine  has  of  late  been  coming  more  into 
general  use,  particularly  for  driving  electrical  generators, 
centrifugal  pumps,  etc.,  and  has  led  the  chief  manufacturers 
to  take  up  its  construction  for  powers  up  to  about  1,000  H.P. 
As  now  developed,  its  cost  may  roughly  be  taken  as  20  per 
cent,  less  than  the  corresponding  slow  speed  engine,  its 
weight  some  25  per  cent,  less,  whilst  as  regards  the  question 
of  upkeep,  the  difference,  so  far  as  present  experience 
goes,  does  not  seem  to  be  considerable. 

In  Figs.  51,  55  and  56  the  high  speed  four-cycle  Sulzer 
engine  is  shown,  the  type  being  similar  for  all  sizes  from  150 
to  1,000  B.H.P.  The  four-cylinder  construction  is  usually 
adopted,  with  a  vertical  three-stage  injection  air  pump 
mounted  on  the  end  of  the  engine,  and  driven  off  the  crank 
shaft  direct  from  an  overhung  crank.  The  engine,  which  runs 
at  300  r.p.m.  for  200  H.P.,  and  220  r.p.m.  for  800  H.P.,  is 
totally  enclosed,  and  forced  lubrication  is  adopted  throughout . 
The  oil  is  forced  through  the  different  bearings  by  a  pump 
driven  off  the  engine,  and  flows  back  into  the  crank  chamber, 
being  drawn  from  the  bottom  by  means  of  another  pump 
through  a  filter  and  an  oil  cooler.  The  consumption  of 
lubricating  oil  is  slightly  higher  than  with  a  low  speed  engine, 
being  in  the  neighbourhood  of  "015  to  "02  lb.  per  B.H.P. 


^^ ih. 


L« 


^j-{.^|^ister  &  Wain  High-Speed  Diesel  Engine. 

[To  face  page  98. 


Fio.   53.— Bnrmeister  &  \\'ain  Higii-Spewl  Diesel  Engir 
[To  face  pnrje  98. 


^Sl 

1 

J 

[To  face  pwje  98. 


Fio.   54.— C'arela'  Higli  S|)oc<l   Diesel   Engi 


I  To  /iiri-  paye  98. 


CONSTRUCTION  OF  THE  DIESEL  ENGINE        99 


100    DIESEL  ENGINES  FOR  LAND  AND  MARINE  WORK 

hour  as  against  "01  to  015  lb.  The  fuel  oil  consumption 
is  also  slightly  in  excess  of  the  slow  speed  motor  to  the  extent 
of  some  5  or  10  per  cent. 

The  cams  which  control  the  fuel  valve  levers  have  steel 
inserted  pieces,  and  the  other  cams  are  arranged  to  have 
large  bearing  surfaces.  All  the  cams  run  in  an  oil  bath,  and 
the  noise  is  reduced  to  a  minimum,  being  in  fact  less  than 
with  a  slow  speed  engine. 

The  design  of  the  high  speed  motor  of  Messrs.  Cards' 
construction  is  somewhat  similar,  and  is  shown  in  section 
in  Fig.  54. 

Horizontal  Engine. — At  present  the  construction  of 
the  horizontal  Diesel  engine  has  only  been  taken  up  to  a 
comparatively  small  extent,  and  this  type  is  something  of 
an  innovation,  inasmuch  as  the  Diesel  motor  has  from  its 
earliest  development  been  considered  essentially  a  vertical 
engine.  There  is  this  to  be  said  in  favour  of  the  horizontal 
type,  that  in  the  past  ten  years  such  a  wide  experience  has 
been  obtained  with  large  horizontal  gas  engines,  and  hence 
advantage  can  be  taken  of  the  knowledge  gained  with  these 
machines,  and  such  knowledge  can  be  well  utilized  in  the 
design  and  construction  of  Diesel  engines  of  the  same 
type,  since  both  types  are  so-called  internal  combustion 
engines  and  present  many  similarities.  Though  naturally 
more  floor  space  is  required  for  a  horizontal  engine,  much 
less  height  is  needed  for  the  installation  and  dismantling, 
and  it  has  to  be  remembered  that  the  pistons  on  Diesel 
engines  of  the  ordinary  type  have  to  be  drawn  out  from  the 
top,  and  this  point  must  not  be  lost  sight  of  in  estimating 
the  necessary  height  of  the  engine  room.  Among  the 
advantages  offered  by  the  horizontal  engine  are  a  reduction 
of  the  pressure  on  the  foundations  due  to  the  greater  surface, 
and  practically  a  complete  absence  of  vibration,  though  it 
must  be  said  that  the  vibration  with  vertical  engines  is  very 
small.  With  a  horizontal  engine  the  piston  can  be  more 
readily  removed  than  in  the  vertical  type,  since  in  a  single 
acting  engine  by  disconnecting  the  connecting  rod,  the 
piston  can  be  drawn  out  of  the  cylinder  from  the  crank  end, 


CONSTRUCTION   OF  THE   DIESEL  ENGINE      101 


leaving  all  the  valve  gear  untouched.  The  connecting  rod  is 
made  of  greater  length  relative  to  the  crank  than  in  vertical 
engines  (six  times  instead  of  fxve)  in  order  to  reduce  the 
pressure  on  the  bottom  of  the  cylinder  due  to  the  obliquity 
of  the  connecting  rod,  and  as  of  course  is  the  case  in  all 
horizontal  engines,  the  pressure  on  the  top  side  of  the 
cylinder  is  partially  counteracted  by  the  weight  of  the  crank 
and  connecting  rod,  which  is  not  the  case  in  vertical  motors. 

The  horizo  n  t  a  1 
Diesel  engine  is 
made  as  a  four  or 
two  cycle  machine, 
and  for  large  sizes 
the  double  acting 
principle  is  e  m  - 
ployed.  For  engines 
under  200  B.H.P.  a 
single  cylinder  is 
usually  employed, 
and  for  larger  sizes, 
two  cylinders  are 
fixed  side  by  side, 
with  the  flywheel  at 
one  end  of  the  crank 
shaft.  For  still 
greater  powers  two 
sets  of  two  cylinder 
engines  are  employed 
with  the  flywheel 
between,    while    for 

the  largest  machines  and  with  double  acting  engines  a 
twin  tandem  arrangement  is  adopted,  and  for  dynamo 
driving  the  generator  is  between  the  two  pairs  of  engines. 
The  four-cycle  type  may  be  constrvicted  in  one,  two,  or 
four  cylinders,  but  the  two-cycle  machine  is  only  built  in 
two  or  four  cylinders. 

The  bed-plate  of  the  horizontal  engine  is  of  the  box  pattern, 
the  outer  cvlinder  covers  being  cast  in  one  with  it,  though 


Fig.   56. — Section  throiigh  High  Speed 
Engine  and  Air  Pump. 


102    DIESEL  ENGINES  FOR  LAND  AND  MARINE  WORK 

generally  bolted  on  in  the  case  of  the  two-cycle  engines. 
The  cylinder  liners  a,re  removable,  and  are  constructed  of 
close-grained  cast  iron.  As  with  vertical  engines,  the 
cylinder  head  which  contains  some  of  the  valves  is  bolted  on 
to  the  main  cylinder  casting,  but  the  arrangement  of  valves 
differs  considerably  from  that  adopted  with  the  vertical 
type.  In  the  four-cycle  type  the  fuel  inlet  valve  is  horizontal 
and  in  the  centre  of  the  cylinder  head,  while  the  starting 
valve  for  admitting  compressed  air  is  arranged  close  to 
the  fuel  valve.  The  exhaust  valve  is  at  the  bottom  of  the 
cylinder  head,  while  the  air  suction  inlet  valve  is  at  the  top, 
both  of  these  valves  being,  of  course,  vertical.  In  the  two- 
cycle  engine  ports  are  adopted,  uncovered  by  the  move- 
ment of  the  piston,  and  both  the  exhaust  and  air  admission 
valves  of  the  four-cycle  machine  are  utilized  as  scavenge 
valves,  through  which  the  air  from  the  scavenge  pump 
enters  the  cylinder.  The  cam  shaft  for  operating  the  valves 
is  horizontal,  driven  off  the  crank  shaft  by  worm  gearing, 
as  in  the  established  practice  for  gas  engines.  The  exhaust 
and  air  admission  valves  (or  the  scavenge  valves  in  a  two- 
cycle  engine)  are  actuated  by  a  single  eccentric  on  the  cam 
shaft,  this  being  possible  since  they  are  symmetrically 
placed,  and  in  two-cylinder  engines  but  one  cam  shaft  and 
eccentric  are  usually  employed,  the  valves  of  the  second 
cylinder  remote  from  the  cam  shaft  being  operated  by  a  con- 
necting lever  between  the  two  valves.  For  the  working 
of  the  fuel  inlet  valves  a  small  subsidiary  shaft  is  driven  off 
the  cam  shaft  through  gearing,  at  right  angles  to  it,  and  an 
eccentric  on  this  small  shaft  actuates  the  inlet  valve  direct. 
In  the  double  acting  machines,  in  order  that  the  piston  rod 
may  not  be  subjected  to  the  highest  temperature,  the  fuel 
is  injected  on  each  side  of  the  piston  in  pockets  which  are 
formed  between  the  cylinder  cover,  the  valve  and  the  piston. 
This  method  is  exceedingly  helpful  in  avoiding  trouble  with 
the  stuffing  boxes. 

The  governor  is  mounted  on  a  vertical  governor  shaft 
driven  off  the  crank  shaft,  and  its  action  is  the  same  as  that 
already  described  for  vertical  engines  in  which  regulation 


[To  face  p:ige  102. 


Fius.  57  onil  ns.— Details  of  M.A.N.  Horiznntnl  En 


CONSTRUCTION  OF  THE  DIESEL  ENGINE      103 

is  obtained  by  variation  of  the  quantity  of  oil  admitted  to 
the  fuel  inlet  valve.  The  eccentric  operating  the  plunger 
of  the  fuel  pump  is  fixed  on  the  cam  shaft,  and  the  oil 
chamber  is  provided  with  a  float.  The  air  compressor  for 
the  provision  of  starting  and  injection  air  is  of  the  horizontal 
two-stage  type,  and  is  driven  direct  off  an  extension  of 
crank  shaft  on  the  same  side  of  the  engine  as  the  cam  shaft. 
In  very  large  four-cycle  engines  the  compressor  is  laid  on  a 
small  foundation  separate  from  the  main  bed-plate,  and 
the  cylinders  are  arranged  so  that  the  centre  is  slightly 
below  the  centre  of  the  crank  shaft.  In  tw^o-cycle  engines 
a  scavenge  pump  is  required,  and  a  different  arrangement  is 
adopted,  the  pump  and  compressor  being  bolted  to  the 
engine  bed-plate  and  arranged  in  tandem.  As  is  common 
in  all  Diesel  engines,  the  air  in  the  compressor  is  cooled 
after  being  compressed  in  the  low  pressure  cylinder  before 
entering  the  high  pressure,  and  is  also  freed  from  water 
and  oil  in  a  separator.  The  supply  of  air  is  controlled  by  a 
throttle  and  blow-oft  valve  in  the  ordinary  way. 

The  exhaust  valves,  as  stated,  are  on  the  bottom  sides  of 
the  cylinder,  and  hence  the  exhaust  pipes  to  the  silencer 
can  be  kept  entirely  below  ground  level,  and  do  not,  as  a 
rule,  require  water  jacketing  to  prevent  radiation,  though  in 
the  two-cycle  engine  w'ater  is  sometimes  sprayed  into  the 
pipe  itself.  In  the  four-cycle  engine  only  the  engine  cylinders 
and  the  compressor  cylinders  and  intermediate  receiver  are 
jacketed,  the  cooling  water  passing  first  through  the  latter, 
but  in  the  two-cycle  machine  the  pistons  are  also  water 
cooled.  All  the  parts  which  are  cooled  have  separate  branches 
and  cocks,  so  that  the  temperature  may  be  varied  exactly 
as  desired.  As  the  air  is  drawn  into  the  cylinders  for  the 
suction  stroke  from  a  pipe  inside  the  bed-plate,  and  the 
exhaust  and  all  other  pipes  are  below  the  floor  level,  the 
appearance  of  the  engine  is  not  disfigured  in  any  way. 

A  considerable  number  of  engines  of  this  type  have  now 
been  constructed  and  are  in  operation,  the  largest  up  to  the 
present  being  one  of  1,600  to  2,000  H.P.— a  four-cylinder 
twin  tandem  four-cycle  double  acting  machine — recently 


104    DIESEL  ENGINES  FOR  LAND  AND  MARINE  WORK 

installed  in  the  Stadiches  Elektrizitatswerk,  Halle  a.  Saale. 
The  cylinder  diameter  of  the  engine  is  650  millimetres  and 
the  stroke  600,  while  the  speed  at  the  normal  output  of  1 ,800 
H.P.  is  150  revolutions  per  minute.  Further  engines  of 
this  type  have  been  constructed,  most  working  on  tar  oil 
with  paraffin  as  ignition  oil  ;  Figs.  57  and  58  give  details  of 
a  standard  M.A.N,  horizontal  engine,  and  Fig.  59  shows 
one  of  £00  H.P. 

The  Deutz  Horizontal  Engine. — The  horizontal  engine 
built  by  the  Gasmotorenfabrik  Deutz  is  in  many  important 
respects  a  different  type  from  that  previously  described. 
It  is,  however,  not  made  in  large  sizes  and  has  been  mainly 
developed  for  cylinders  up  to  about  50  H.P.  It  may  inci- 
dentally be  mentioned  that  with  such  small  powers  in 
this  country  (Great  Britain)  the  Diesel  engine  has  not  found 
general  favour  owing  to  the  success  which  has  been  attained 
with  the  hot-bulb  motor,  since  the  cost  of  installation  of 
the  Diesel  type  is  generally  in  excess  of  that  of  the  other 
design,  and  the  difference  in  fuel  consumption  in  such  small 
sizes  is  usually  scarcely  sufficient  to  warrant  the  extra  cost 
involved.  On  the  Continent,  however,  very  large  numbers 
of  these  small  horizontal  engines  are  manufactured  and 
sold,  and  practically  all  those  which  are  employed  in 
Germany  run  on  tar  oil,  which,  as  mentioned  elsewhere, 
can   be   obtained   at   a  relatively   low   price. 

In  main  construction  the  engine  follows  somewhat  along 
the  lines  of  accepted  horizontal  gas  engine  practice.  The 
cylinder  jacket  and  bed-plate  are  in  one  piece,  and  the 
horizontal  cam  shaft  is  driven  through  gearing  off  the  crank 
shaft.  From  the  illustration  of  the  engine  which  is  given 
in  Fig.  60  it  will  be  noticed  that  the  suction  air  valve  is 
vertical  with  a  silencer  above  it,  whilst  the  exhaust  valve 
is  immediately  below  this  suction  valve.  The  fuel  inlet 
valve  is  horizontal  and  is  arranged  in  the  centre  of  the 
cylinder  cover,  which  also  contains  the  two  valves  previ- 
ously mentioned  and  the  starting  air  valve,  AAliich  is  on  the 
side  of  the  cover.  Naturally,  this  construction,  and  indeed 
any  form  of  horizontal  engine,  does  not  give  the  most  perfect 


{To  J  ace  page  10 1. 


To  Jace  jxuje  10 1. 


105 


106    DIESEL  ENGINES  FOR  LAND  AND  MARINE  WORK 

combustion  chamber  for  a  Diesel  engine,  but  from  the 
results  which  are  attained,  viz.  a  consumption  of  about 
•45  lb.  of  oil  per  B.H.P.  hour,  it  appears  that  the  effect 
is  not  serious. 

The  arrangement  of  the  air  compressor  is  interesting 
inasmuch  as  it  is  of  the  vertical  two-stage  type  driven  by 
a  small  crank  from  the  end  of  the  crank  shaft  through  worm 
gearing.  The  cooler  is  concentric  with  the  pump  barrels, 
and  an  interesting  modification  in  this  motor  from  other 
types  lies  in  the  fact  that  the  air  for  injection  is  delivered 
direct  to  the  fuel  valve  from  the  high  pressure  cylinder,  no 
injection  air  reservoir  being  provided.  The  reason  for  this 
is  explained  later.  For  starting  purposes  it  is,  of  course, 
necessary  to  have  compressed  air,  and  in  this  case  the 
pressure  is  under  200  lb.  per  sq.  inch,  the  diminished  pressure 
being  compensated  by  an  increased  opening  of  the  starting 
air  valve. 

A  special  arrangement  of  fuel  pump  and  fuel  valve  is 
provided,  the  method  adopted  being  to  pump  the  fuel  to  the 
valve  just  at  the  moment  when  it  is  opening  so  that  it  is 
injected  direct  by  the  compressed  air.  The  governing  of 
the  amount  of  oil  pumped  into  the  cylinder  through  the 
injection  valve  is  carried  out  by  controlling  the  delivery 
from  the  fuel  pump,  which  is  arranged  with  an  overflow 
by-pass  instead  of  the  suction  valve  as  is  common  with  most 
types  of  Diesel  motors.  When  tar  oil  is  utilized  with 
this  engine  there  is  a  small  auxiliary  pump  and  a  separate 
inlet  to  the  fuel  valve,  by  means  of  which  the  ignition  oil, 
such  as  gas  oil,  is  pumped  direct  into  the  fuel  pump  chamber 
and  thus  into   the  combustion  chamber  before  the  tar  oil. 

Two-Cycle  Engine. — Exclusive  of  exceptional  circum- 
stances it  may  be  taken  that  for  powers  up  to  600  or  700 
B.H.P.  the  four-cycle  single  acting  engine  will  be  employed 
for  land  work,  and  above  that  power  the  two-cycle  engine 
will  be  frequently  adopted,  or  in  certain  cases  the  double  act- 
ing two  or  four-cycle  type.  In  four-cycle  engines  of  large 
powers  the  engine  frame,  bed-plate,  and  flywheel  become  so 
heavy  as  to  render  them  unwieldy,  and  the  main  disadvantage 


CONSTRUCTION   OF  THE  DIESEL  ENGINE      107 

of  the  two-cycle  motor — namely  the  necessity  of  a  scavenge 
pump — becomes  of  less  relative  importance  than  is  the  case 
with  smaller  engines,  when  the  slight  extra  complication  of 
the  two-cycle  engine  is  undesirable.  The  difference  in  con- 
struction and  external  appearance  between  the  two  and  four 
cycle  engines  is  small,  and  is  chiefly  marked  by  the  addition 
of  the  air  scavenging  pump  or  pumps  commonly  mounted 
on  the  end  of  the  bed-plate,  though  in  some  types  of  engine 
it  is  arranged  underground  beneath  the  bed-plate.  The 
speed  of  two-cycle  engines,  which  are  seldom  made  in  sizes  of 
less  than  SCO  H.P.  and  are  usually  700  H.P.  and  upwards,  is 
from  about  ISO  to  IcO  revolutions  per  minute  or  rather  less. 
The  exhaust  valves  of  the  four-cycle  engine  are  replaced 
by  ports  at  the  bottom  of  the  cjdinders,  uncovered  by  the 
piston  as  it  moves  outwards,  and  this  is  in  itself  a  simplifi- 
cation of  the  construction.  In  present  designs  of  this  type 
of  motor,  the  scavenging  air  is  admitted  through  valves  in 
the  cylinder  cover,  operated  from  the  horizontal  cam  shaft  in 
the  usual  way,  but  as  is  the  case  with  marine  engines,  it 
is  probable  that  an  arrangement  in  which  ports  are  employed 
will  be  generally  adopted  in  the  future.  Such  a  method  is 
already  being  used  by  Messrs.  Sulzer,  and  the  exhaust  ports 
are  arranged  on  one  side  of  the  cylinder,  while  the  scavenge 
ports  are  on  the  other  side.  In  large  engines,  and  particu- 
larly with  marine  engines,  not  only  is  the  admission  of  fuel 
controlled  for  varying  the  power  of  the  engine,  but  the 
admission  of  scavenge  air  to  the  working  cylinders  is  auto- 
matically limited  with  decreasing  load,  as  if  this  were  not 
done,  there  would  be  a  considerable  excess  of  air  and  conse- 
quently inefficient  operation. 

Fig.  61  shows  a  two-cycle  single  acting  four-cylinder 
Diesel  motor  of  Messrs.  Sulzer's  construction.  It  is  of 
2,4.00  B.H.P.  and  is  employed  for  dynamo  driving  in 
a  central  electric  station  in  France.  There  are  two 
scavenge  cylinders  on  the  end  of  the  bed-plate  driven 
direct  off  the  crank  shaft,  while  the  three- stage  air 
compressors,  of  which  there  are  also  two,  are  arranged,  the 
low  pressure  stages  below,  the  middle  and  high  pressure 


108    DIESEL  ENGINES  FOR  LAND  AND  MARINE  WORK 

stages  behind  the  scavenge  pumps.  The  latter  stages  are 
driven  by  means  of  rocking  levers.  The  ordinary  open  type 
A  frame  is  adopted  and  the  cylinder  body  and  the  frame  are 
cast  in  one  piece  in  each  cylinder  and  provided  with  a  liner 
as  with  four-cycle  engine,  while  the  usual  trunk  piston  is 
adopted.  Each  cylinder  is  provided  with  a  starting  lever 
and  valve  so  that  the  engine  may  be  run  up  in  almost  any 
position,  this  being  a  necessity  in  view  of  the  size  of  the 
motor.  The  horizontal  cam  shaft  is  totally  enclosed,  and 
all  the  cams  run  in  oil,  the  operation  of  the  engine  being 
therefore  particularly  silent.  The  cooling  water  oi.tlet 
pipes  are  clearly  seen  in  front  of  the  engine,  there  being  one 
for  each  cylinder,  delivering  into  an  open  funnel  so  that  the 
flow  is  visible,  and  the  temperature  can  be  readily  measured. 
The  pistons  are  also  water  cooled,  and  the  outlet  water  flows 
into  the  same  funnel  as  the  jacket  water,  and  is  delivered 
thence  into  the  main  delivery  pipe.  Fig.  62  shows  an 
outline  plan,  front  elevation  and  side  elevation,  of  the  engine 
with  overall  dimensions,  from  which  it  is  seen  that  the  over- 
all length  is  42  ft.  4  in.  inclusive  of  the  flywheel.  There  are 
two  silencers  placed  underground,  and  the  main  exhaust 
pipe  from  the  engine  to  the  silencer  is  also  below  the  engine 
room  floor,  the  exhaust  gasses  from  each  cylinder  being 
delivered  into  this  main  pipe  by  a  separate  pipe  seen  in 
Fig.  61. 

There  has  recently  been  a  tendency  to  construct  the 
large  two-cycle  engines  for  stationary  work  exactly 
similar  to  the  marine  type  except  for  the  reversing  gear — 
a  tendency  much  to  be  commended.  In  the  engines  of 
4,000  B.H.P.  which  Messrs.  Sulzer  are  building,  this  pro- 
cedure has  been  adopted,  and  in  general  design  such  motors 
are  the  same  as  the  marine  engines  described  later  in 
detail. 

In  the  4,000  B.H.P,  type  there  are  six  cylinders,  each  of 
30  in.  diameter  and  40  in.  stroke,  the  speed  of  rotation  for 
full  load  being  132  revolutions  per  minute.  Two  scavenge 
pumps  are  arranged  at  the  end  of  the  engtne,  driven  direct 
off  the  crank  shaft,  and  between  these  cylinders,  also  driven 


[To  face  page  108. 


Fio,  ()).— Suber  Two-Cyclc  2.400  B,H  P.   Engine 


[To  lace  poje  108. 


CONSTRUCTION   OF  THE   DIESEL   ENGINE       109 


^^^^\\>^^^^^^^^^^^^^^^ 


fc 


direct  off  the  crank  shaft,  are  the  high  and  intermediate 
pressure  stages  of  the  fuel  injection  pump.     The  crossheads 


CONSTRUCTION   OF  THE   DIESEL   ENGINE       111 


Fig.   C4. — Section  througli  Cylinder  of  Siilzer  Two-Cycle  Motor,  showing 
auxiliary  scavenge  ports. 


112    DIESEL  ENGINES  EOR  LAND  AND  MARINE  WORK 


of  the  scavenge  pump  are  arranged  as  the  two  low  pressure 
stages  of  the  injection  air  compressor. 


CONSTRUCTION   OF   THE   DIESEL  ENGINE       113 

The  method  of  scavenging  is  identical  with  that  employed 
in  the  marine  engines  and  described  later.  (Scavenge  valves 
in  the  cjdinder  head  are  dispensed  with,  ports  being  provided 
at  the  bottom  of  the  cylinder,  uncovered  by  the  piston, 
whilst  auxiliary  valve-controlled  air-ports  are  also  arranged 
just  above  the  main  ports.  Only  three  of  the  cyhnders 
have  starting  valves,  and  in  each  case  there  are  two  valves  in 
the  cylinder  head,  whilst  each  cylinder  has  one  fuel  inlet 
valve.     No  other  valves  are  required. 

An  important  feature  of  the  engine  and  one  which  is  much 
adopted  in  various  marine  designs,  is  that  the  cylinder  is 
supported  by  steel  columns  and  not  by  a  cast-iron  frame. 
The  cylinder  liner  itself  is  quite  free  to  move  downward 
during  expansion,  which  is  a  necessary  safeguard  in  large 
cylinders. 

The  weight  of  this  engine  complete  is  some  4r0  tons,  and 
its  length  about  55  ft. 

A  similar  principle  is  followed  in  the  design  adopted  by 
Messrs.  Cards  in  their  large  two-cycle  engines,  which  are 
built  up  to  2,500  H.P.  in  six  cylinders.  Fig.  68  shows  a  1 ,000 
B.H.P.  stationary  engine  of  four  cylinders  of  the  standard 
two-cycle  type,  running  at  125  revolutions  per  minvite. 
Except  that  no  reversing  mechanism  is  provided,  and  the 
scavenge  pump  is  driven  direct  off  the  crank  shaft  instead 
of  by  means  of  rocking  levers  off  the  erossheads,  the  motor 
is  almost  identical  with  the  Carels  marine  engine  which  is 
described  later. 

The  motor  is  of  the  open  type,  somewhat  resembling  a 
steam  engine  in  appearance,  and  the  trunk  piston  has  been 
dispensed  with  in  favour  of  the  crosshead  and  connecting  rod 
■ — a  step  which  seems  advisable  for  motors  of  large  power. 
The  cylinders  are  supported  on  "  A  "  frames,  and  a  Reavell 
three-stage  air  compressor  (not  seen  in  the  illustration)  is 
employed,  driven  direct  off  the  crank  shaft  in  the  usual 
manner. 

There  is  much  to  be  said  in  favour  of  arranging  the  scavenge 
pump  on  the  end  of  the  bed-plate,  instead  of  by  levers  as  in 
the  marine  type  ;  in  the  latter  the  method  is  objected  to  by 

I 


J 


"  (New  Type). 


[To  face  page  114. 


Sc3/e  of  Millimetres 

Isoo    iOO    lOd                     \poo 

\sooo 

k 

Fio.   li(i. — Cards  Two-Cycle  Sttitionury  Motor  {N'l-w  Typi 


[To  face  page  114. 


^^^^^    ^^.^^.aa;--^^^,j»caas>- 


\'m.   07.— rUin  .,(  CorHs'  Two-Cylc  Sl.itinnnry  Motor  (Nnv  T>-pi^: 


iro/m.  ;»i</.-  114. 


[To  face  page  114. 


Fig.  *  19,— Elevation  of  Ctirels  Two-Stroke  Stationary  Motor  (New  Tj-pe). 


1 


[To  face  page  1 14. 


Viu.   70.— Dotaile  c.f  Senvongo  Pump  nnil  A[v  Comprosmir  tor  Ciin'l»'  T»n-Stroko  St.Qti.iniir.v  Mnlur  (NVw  Typr). 


[T^lmc  pa^r  111. 


71. —Cards'  Two-Cj'cle  Stationarj'  Engine  of  1,000  H.P. 

[To  face  page  114. 


y.^s^\  /^^  'p'-'-^^t  lui 


Fki.  71.— Cur<-ls-  Tivo-C'yeli^  Stationary  Engine  of  1,000  H.P. 
[To Im  page  \U. 


CONSTRUCTION   OF  THE   DIESEL   ENGINE       115 

some  makers  owing  to  the  increase  in  length  of  the  engine, 
as  there  is  generally  more  available  space  at  the  side,  and 
moreover  the  engine  cannot  be  made  so  symmetrical,  which 
is  a  point  of  some  importance  in  considering  the  spare 
parts — for  instance,  the  crank  shaft  can  be  made  in  two 
eqvial  portions.  This  is  not  possible  \\ith  a  design  in  which 
the  scavenge  pump  is  mounted  on  the  end  of  the  engine. 

In  common  with  all  the  present  two-cycle  Carels  designs, 
valves  are  utilized  for  scavenging,  fitted  in  the  cylinder 
cover,  two  or  four  being  adopted. 

Figs.  66  to  71  show  the  most  recent  type  of  Carels'  two- 
cycle  engines,  the  main  modification  being  in  the  air  com- 
pressors. 

Air  Compressors  for  Diesel  Engines. — The  air  com- 
pressors for  the  supply  of  injection  air  and  for  starting 
purposes,  are  very  important  features  of  the  Diesel  engines, 
and  as  the  power  absorbed  by  them  is  practically  a  dead  loss 
from  a  commercial  standpoint,  a  large  amount  of  care  has  been 
bestowed  upon  their  design  to  render  them  as  economical 
and  efficient  as  possible,  more  particularly  as  such  high 
pressures  as  nearly  1 ,000  lb.  per  sq.  inch  have  to  be  obtained. 
Air  compressors  for  Diesel  engines  may  roughly  be  divided 
into  two  classes  :  (1 )  the  vertical  type  driven  either  by  levers 
off  the  connecting  rod,  or  direct  from  the  crank  shaft  at  one 
end  of  the  engine  ;  and  (2)  those  of  the  Reavell  or  similar 
type,  in  which  all  the  pistons  are  driven  from  eccentrics  on 
the  end  of  the  crank  shaft.  Owing  to  the  high  pressure, 
single  stage  compressors  are  seldom  used,  the  common  type 
being  either  two  stage  or  three  stage  compressors. 

In  the  Diesel  engine  of  some  of  the  German  types  a 
separate  compressor  is  often  provided  for  each  cylinder. 
The  air  is  drawn  from  the  atmosphere  into  the  low  pressure 
cylinder,  and  after  being  compressed  by  the  piston,  it  passes 
into  a  receiver,  and  thence  to  the  high  pressure  cylinder. 
Here  it  is  further  compressed  and  is  delivered  through  a 
valve  to  the  air  reservoirs.  There  are  two  siiction  valves 
which  open  outwards  and  allow  air  to  enter  the  cylinder 
through  small  passages,  being  returned  through  the  same 


IIG    DIESEL  ENGINES  FOR  LAND  AND  IVIARLNE  WORK 


ports  after  compression  and  delivered  to  the  receiver  through 
outlet  valves  which  open  inwards.  The  cylinders  and 
receiver  are  well  water  jacketed  as  the  temperature  of  the 
air  naturally  rises  considerably  during  compression. 


Fig.   73. — Reavell  Quadrviplex  Compressor. 

The  well-known  Quadruplex  form  of  single  stage  "  Eea- 
vell  "  compressor  has  been  suitably  modified  and  used  very 
largely  by  different  makers  of  Diesel  engines.  Its  general 
appearance  for  Diesel  engines  of  the  land  type  is  shown  by 
the  illustration  Fig.  73  and  the  two  sections  in  Fig.    14:. 


CONSTRUCTION  OF  THE   DIESEL  ENGINE       117 


In  these  machines  the  compressing  of  the  air  is  carried  out 
in  three  stages,  which  is  found  to  give  better  results  than  with 
the  two  stage  compressors  used  in  earlier  Diesel  engines. 


118    DIESEL  ENGINES  FOR  LAND  AND  MARINE  WORK 


Fig.   7().  —Section  of  Three-Stage  Vertical  Compressor  for  Diesel  Engines. 


The  two  horizontal  cylmders  seen  in  the  illustrations  are 
both  low  pressure  cylinders,  so  that  at  each  stroke  of  the 


[To  lace  page  1 10 


CONSTRUCTION  OF  THE   DIESEL  ENGINE      119 

engine  low  pressure  air  is  passed  over  into  the  intermediate 
cylinder.  The  air  is  admitted  into  the  crank  chamber  of 
the  compressor,  whence  it  passes  through  ports  in  the  gud- 
geon and  piston  during  the  suction  stroke,  so  that  the  cyhn- 
ders  are  filled  with  air  at  atmospheric  pressure,  without  the 
attenuation  due  to  the  use  of  suction  valves. 

On  the  delivery  stroke  the  ports  referred  to  are  closed 
by  the  swing  of  the  connecting  rod,  which  moves  the  ports 
in  the  gudgeon  away  from  the  ports  in  the  piston,  and  thus 
the  air  is  compressed  and  delivered  through  the  delivery 
valve  and  cooled  by  means  of  the  coil  seen  in  Fig.  74  and 
then  delivered  into  a  second  chamber  or  purge  pot,  from 
which  again  any  moisture  which  is  separated  out  can  be 
blown  off. 

The  air  then  passes  through  another  pipe  to  the  high 
pressure  cylinder  placed  at  the  top  of  the  machine,  which 
contains  suction  and  delivery  valves  interchangeable  with 
those  on  the  intermediate  cylinder.  After  the  final  stage  of 
compression  in  this  cylinder,  the  air  is  passed  through 
the  coiled  pipe  shown,  to  the  delivery  bonnet,  whence  it 
passes  to  the  air  storage  bottles,  which  supply  the  Diesel 
engine. 

Machines  of  this  type  are  made  in  standard  sizes  for  Diesel 
engines  from  about  100  H.P.  at  medium  speed  up  to  the 
large  sizes. 

The  whole  of  the  compressing  cylinders  being  arranged  in 
a  symmetrical  form  of  casing,  it  is  possible  to  bolt  this  casing 
directly  to  the  end  of  the  bed-plate  of  the  Diesel  engine,  so 
that  no  extra  bearing  is  required  for  the  compressor.  The 
crankpin  for  driving  the  connecting  rods  and  pistons  is 
simply  attached  direct  to  the  end  of  the  standard  crank 
shaft  of  the  Diesel  engine  by  means  of  studs,  or  any  other 
simple  manner,  the  crank  disc  of  course  being  carefully 
spigoted  to  a  recess  in  the  shaft,  so  as  to  form  a  register  and 
insure  correct  alignment. 

Fig.  75  shows  a  type  of  vertical  three  stage  compressor 
made  by  Messrs.  Reavell  &  Co.  for  high  speed  Diesel  engines. 
It  embodies  a  novel  feature  in  its  construction,  as  the  valves 


120    DIESEL  ENGINES  FOR  LAND  AND  MARINE  WORK 

in  the  intermediate  cylinder,  both  for  suction  and  deHvery, 
are  altogether  omitted. 

As  will  be  seen  by  the  illustration,  all  of  the  cylinders  are 
placed  vertically,  the  low  pressure  and  high  pressure  cylinders 
being  above  the  crankpin  and  in  tandem  with  each  other, 
while  the  intermediate  cylinder  is  below  the  crankpin.  The 
same  provision  for  the  admission  of  air  in  the  low  pressure 
cylinder  through  the  gudgeon  ports,  already  described  for 
the  Quadruplex  compressor,  is  made  use  of  for  this  new 
vertical  type,  thus  omitting  the  suction  valves.  Delivery 
valves  are  provided  on  the  low  pressure,  from  which  a 
suitable  design  of  pipe  connexions  leads  the  air  to  the  bottom 
of  the  intermediate  cylinder  and  onwards  from  the  inter- 
mediate cylinder  up  to  the  suction  valve  on  the  high  pressure 
cylinder. 

By  suitably  proportioning  the  volumes  of  tliese  pipes  and 
the  volume  of  the  intermediate  cylinder,  the  air  during  the 
second  stage  of  compression  is  pushed  backwards  into  the 
pipe  leading  to  the  high  pressure  cylinder,  and  cooling  takes 
place  during  the  very  act  of  compression,  which  enhances  the 
efficiency. 

During  the  next  stroke,  the  pressure  behind  the  inter- 
mediate piston  falls  as  the  air  expands,  until  the  low 
pressure  delivery  valves  open  again  and  the  next  charge  of 
air  is  passed  over  from  the  low  pressure.  On  the  succeeding 
compression  stroke  of  the  intermediate  cylinder,  the  air 
passed  over  from  the  low  pressure  cylinder,  together  with 
the  air  which  remains  in  the  intercooler  pipe  connexion,  is 
again  compressed.  At  the  same  time  the  high  pressure 
cylinder  is  performing  its  suction  stroke,  so  that  the 
increasing  intermediate  pressure  rapidly  reaches  a  point 
when  the  suction  valve  on  the  high  pressure  opens  and 
some  of  the  intermediate  air  is  passed  over  into  the  high 
pressure  cylinder.  This,  during  the  next  stroke,  is  com- 
pressed by  the  high  pressure  plunger  and  delivered  ;  and 
the  cycle  is  repeated. 

In  other  respects  the  compressor  is  the  same  as  Messrs. 
Reavell's  Quadruplex  compressor,  that  is  to  say,  it  has  no 


Via.  77.— General  Arriingemimt   i>t  (Jomim'.^or   fur  Curcln    l.SDO   H.l'.  ')'w[i-(;yrli'  Mnrino  liiii!! 


[T,:l,we  p'm  12 1- 


CONSTRUCTION   OF  THE  DIESEL  ENGINE      121 

bearings  and  the  crankpin  is  attached  to  the  end  of  the  shaft 
in  just  the  same  way. 

For  small  and  very  high  pressure  engines  this  vertical  com- 
pressor is  attached  direct  to  the  bearers  which  also  carry  the 
engine,  brackets  being  cast  on  the  sides  of  the  compressor 
for  this  purpose.  For  larger  engines  a  segmental  facing  is 
provided  on  the  back  of  the  compressor  casing,  attached 
directly  to  a  similar  facing  on  the  engine  bed. 

The  advantage  of  this  type  of  machine  is  that  all  valves 
below  the  centre  line  of  the  compressor  are  entirely  done 
away  with,  and  this  not  only  simplifies  the  machine  and 
improves  its  efficiency,  but  also  makes  periodical  over- 
hauling quite  an  easy  matter.  It  will  be  seen  that  the  only 
valves  requiring  attention  are  rendered  accessible  by  lifting 
the  top  water  bonnet,  which  uncovers  both  low  pressure  and 
the  high  pressure  cylinders,  and  in  all  these  compressors 
the  whole  of  the  valves  and  caps  are  completely  surrounded 
with  water,  which  experience  has  shown  will  obviate  the 
trouble  arising  from  the  gumming  up  of  valves  due  to  the 
heating  of  the  air. 

For  marine  work  a  somewhat  similar  quadruplex  com- 
pressor is  emploj^ed,  there  being  two  modifications  in  the  con- 
struction. A  section  of  this  marine  type  is  shown  on  Fig.  78, 
and  in  comparing  this  with  the  sectional  illustration  of  the 
land  type  of  compressor,  it  will  be  noticed  that  the  guide 
of  the  intermediate  cylinder  is  removed  and  the  valves  are 
placed  in  pockets  on  the  side  of  the  cylinder  instead  of 
at  the  bottom.  The  omission  of  the  guide  is  rendered  pos- 
sible owing  to  the  increased  dimensions  of  these  larger  com- 
pressors for  marine  work,  and  the  alteration  in  the  position 
of  the  valves  enables  a  fiat  bottom  to  be  provided  for  the 
compressor  casing  and  makes  it  easy  to  place  the  casing 
directly  on  the  tank  tops  in  the  ship  or  the  engine  seatings, 
in  the  same  way  as  the  bed  of  the  Diesel  engine  itself. 

As  the  compressor  must  be  capable  of  compressing  its  air 
satisfactorily,  whether  the  engine  is  running  ahead  or  astern, 
the  gudgeon  inlet  for  the  first  stage  air,  which  is  adopted  in 
the   land   type    of   compressor   already   described,  is   here 


122    DIESEL  ENGINES  FOR  LAND  AND  IVLIRINE  WORK 

replaced  by  ordinary  suction  valves,  which  obtain  their  air 
from  a  port  leading  into  the  crank  chamber. 

In  Fig.  77  are  given  details  of  a  Carels  compressor  for  a 
1,500  H.P.  motor,  driven  by  means  of  levers  from  the 
crosshead  of  the  engine. 

Solid  Injection  for  Diesel  Engines. — When  the  first 
experiments  were  first  being  made  en  Diesel  engines  by 
Dr.  Diesel,  it  was  attempted  to  carry  out  the  cycle  of  opera- 
tions simply  by  forcing  the  fuel  into  the  combustion  cham- 
ber under  pressure  from  a  pump.  This  was  found  to  be 
unsatisfactory  and  was  entirely  abandoned.  It  was  not 
until  recently  that  any  actual  progress  was  made  in  the 
direction  of  solid  injection  for  Diesel  engines,  and  at  the 
present  time  motors  working  on  this  principle  are  built 
only  by  Messrs.  Vickers  for  submarine  engines . 

The  advantages  of  the  abolition  of  the  air  compressor 
for  injecting  air  are  obvious,  particularly  as  it  is  found 
that  in  high-speed  engines  the  air  compressor  represents 
one  of  the  auxiharies  most  liable  to  cause  trouble,  and  even 
with  the  ordinary  slow-speed  marine  engine,  air  compressors 
often  need  special  attention.  It  must  be  remembered, 
however,  that  compressed  air  is  necessary  for  starting 
purposes  on  most  engine  %  whilst  it  is  also  required  for 
other  purposes  on  board  ship.  In  motors  for  submarines 
this  does  not  invariably  apply,  as  starting  may  be  ac- 
complished by  means  of  the  electric  motor  which  is 
installed  for  propelling  the  submarine  when  luider  water. 
Reversing  may  be  carried  out  in  the  same  way,  that  is  to 
say,  the  astern  power  being  provided  only  by  the  electric 
motors.  Naturally  this  is  not  in  all  respects  satisfactory, 
but  for  the  purpose  is  not  altogether  unsuitable  for  sub- 
marines as  at  present  constructed,  although  when  larger 
sizes  become  common,  direct  reversibility  will  be  a  necessity. 

(Solid  injection  is  now  being  employed  with  a  large  num- 
ber of  engines  installed  in  British  submarines,  and  has  on 
the  whole  proved  extremely  satisfactor3\  In  these  vessels, 
however,  a  comparatively  light  oil  is  commonly  employed, 
and  although  experiment  seems  to  have  demonstrated  the 


[To  face  page  122 


[To  /ace  pa.je  li 


CONSTRUCTION   OF  THE   DIESEL   ENGINE       123 

possibility  of  utilizing  the  heaviest  oil,  including  the 
Texas  oil  and  tar  oil,  no  commercial  application  has  yet 
been  made.  It  is  hardly  probable  that  the  combustion 
with  solid  injection  can  be  so  satisfactory  as  with  the 
employment  of  compressed  air  for  the  purpose,  but  on  the 
other  hand,  the  power  required  to  drive  the  compressor 
is  eliminated,  which  is  a  matter  of  seven  to  ten  percent,  in 
many  Diesel  engines.  As  a  heat  engine,  however,  the 
motor  with  solid  injection  is  not  so  efficient  as  the  pure 
Diesel  type  with  air  injection,  so  that  the  advantage  obtained 


Fig.   79. — Diagram  of  Vickers"  Solid  Injection  System. 


by  the  abolition  of  the  air  compressor  is  to  a  certain  extent 
counteracted.  On  the  whole,  the  fuel  consumption  with 
this  type  is  approximately  the  same  as  the  ordinary  engine 
using  air  injection. 

The  principle  of  the  arrangement  for  solid  injection  is 
shown  in  Figs.  79  and  80,  these  being,  of  course,  diagram- 
matic in  every  respect.  The  main  idea  is  that  oil  should  be 
pumped  into  a  tube  with  collapsible  walls  which  expand 
under  the  high  pressure,  the  oil  entering  the  tube,  and  on 
the  opening  of  the  fuel  valve  the  walls  collapse,  forcing 


124    DIESEL  ENGINES  FOR  LAND  AND  MARINE  WORK 

the  oil  under  high  pressure  through  the    fuel    valve    into 
the  combustion  chamber. 

In  Fig.  19  C  represents  the  pipe  supplying  oil  from  the 
oil  pump,  while  A  is  the  pressure  tube  referred  to.  B  is 
the  pipe  leading  to  the  injection  valve  which  is  shown  in 


Fig.   80. — Sketch  showing  Sohd  Injection  Arrangement. 

the  diagram  at  D.  The  pressure  tube  is  usually  made 
elliptical,  and  is  forced  into  a  cylindrical  shape  for  the  oil 
under  pressure,  which  may  be  as  much  as  2,000  lb.  to  the 
sq.  inch  or  perhaps  more.  There  is  a  distance  piece  within 
this  collapsible  tube  in  order  to  prevent  it  collapsing  to  too 
great  an  extent. 

This  arrangement  has  hitherto  been  applied  on  a  com- 
mercial scale  to  four-cycle  engines,  though  others  of  the 
two-cycle  type  are  under  construction.  It  is  also  likely 
to  be  adapted  for  mercantile  work,  that  is  to  say  for  marine 
motors  of  the  four-cycle  type  running  at  normal  speeds  of 
revolution  of  100  to  150  r.p.m. 


CHAPTER    IV 
INSTALLING  AND   RUNNING  DIESEL   ENGINES 

GENERAL  REMAEKS — SPACE  OCCUPIED  AND  GENERAL  DIMEN- 
SIONS— ^STARTING  UP  THE  ENGINE — MANAGEMENT  OF 
DIESEL  ENGINES — COST  OF  OPERATION  OF  DIESEL 
ENGINES. 

General  Remarks. — The  Diesel  engine  is  perhaps  the 
most  scientifically  designed  motor  in  existence,  and  for 
that  reason  all  its  parts  have  to  be  constructed  with  great 
exactitude.  From  this  point  of  view  it  may  be  considered 
as  a  delicate  machine,  and  up  to  the  time  when  the  engine 
is  actually  put  to  work  no  emphasis  is  too  strong  as  to 
the  necessity  of  the  utmost  care  to  be  taken,  though  after 
it  is  once  in  operation  it  becomes  a  machine  of  the  greatest 
reUability,  needing,  on  the  whole,  less  care  and  attendance 
than  a  steam  engine  or  gas  engine.  The  installation  of  a 
Diesel  engine  therefore  should  be  carried  out  with  the  same 
precision  as  its  construction,  and  not  be  accompanied  by 
the  careless  manipulation  which  is  customary  with  steam 
plants.  Above  all,  dust  of  any  sort  must  be  prevented 
from  access  to  the  essential  working  parts  of  the  engine, 
particularly  the  fuel  valve,  which  is  very  sensitive  to  any 
minute  particles,  owing  to  the  restricted  inlet  passages 
for  the  air  and  fuel. 

The  foundations  required  are  relatively  heavy,  as  is  the 
case  with  all  vertical  engines,  but  0"«ing  to  the  evenness 
of  combustion  and  the  absence  of  shock  from  the  explosion 
of  mixed  gases,  there  is  less  vibration  than  ^vith  a  gas  engine 
of  similar  type.     The  depth  to  which  it  is  necessary  to 

125 


126  DIESEL  ENGINES  FOR  LAND  AND  MARINE  WORK 

carry  the  foundations  depends  of  course  to  some  extent 
on  the  nature  of  the  subsoil,  as  it  is  essential  to  reach  a  firm 
basis.  Holes  are  left  in  the  concrete  while  the  foundation 
is  being  built  up,  for  the  foundation  bolts,  either  by  means 
of  boxes  or  pipes  of  ample  size,  which  are  withdrawn  when 
the  foundation  is  set.  The  bolts  are  thus  put  in  when  the 
engine  is  being  installed,  and  in  the  usual  arrangement  an 
arched  tunnel  is  left  under  the  foundation  so  that  a  man 
may  have  access  from  the  flywheel  pit  for  tightening  up 
aU  the  bolts  when  the  bed-plate  is  fixed  in  its  exact  posi- 
tion ready  for  grouting  up.  It  is  desirable,  particularly 
where  engines  are  installed  in  existing  buildings  when  the 
vibration  of  the  engine  might  possibly  be  transmitted 
through  the  walls,  to  keep  the  engine  foundations  well  clear 
of  the  foundations  and  footings  of  the  walls.  In  cases 
where  two,  three  or  four  engines  are  erected  in  a  somewhat 
confined  space,  which  frequently  happens  in  installations 
in  the  basements  of  large  buildings,  a  good  plan  is  to  make 
a  through  foundation  upon  which  all  the  engines  are  placed, 
and  this  is  a  method  that  has  frequently  been  adopted. 

The  third  outer  bearing  is  always  separate  from  the  bed- 
plate, and  this  has  to  be  carefully  lined  up  with  the  other 
bearings,  and  the  crank  shaft  is  dropped  in  and  all  the  bear- 
ings scraped  till  it  is  perfectly  true,  this  being  necessary 
even  though  the  engine  has  already  been  running  on  the 
test  bed,  as  there  are  bound  to  be  variations  when  it  is 
actually  installed.  The  crank  shaft  is  lifted  out  and  re- 
placed after  the  bottom  half  of  the  flywheel  is  lowered  in 
the  pit,  and  the  erection  of  the  rest  of  the  engine  is  a  straight- 
forward matter,  particularly  so,  as  in  the  case  of  multi- 
cylinder  engines,  all  parts  of  the  different  cj'lindcrs  being 
interchangeable.  The  two  starting  vessels,  and  the  air 
injection  vessel,  being  commonly  some  six  or  seven  feet 
high,  are  usually  let  into  the  floor  three  or  four  feet  so  that 
all  the  valves  are  at  a  convenient  height  for  operation  by 
the  driver. 

Space  Occupied  and  General  Dimensions. — The 
space   required   for   a   Diesel   engine   installation    \nth   all 


INSTALLING   AND  RUNNING   DIESEL   ENGINES     127 


accessories  is  much  less  than  for  a  complete  gas  or  stoam 
plant.  The  following  table  (Table  I)  gives  the  approxi- 
mate space  necessary 
with  Sulzer  Diesel 
engines,  of  the  stan- 
dard four-cycle  slow 
speed  type,  the  dimen- 
sions referring  to  the 
outline  drawing  Fig. 
8 1,  Many  of  t  he  mea- 
surements can  be  re- 
duced if  it  is  essential, 
owing  to  limitations 
of  the  engine-room, 
and  with  engines  of 
the  high  speed  tjrpe 
all  the  dimensions  be- 
come somewhat  less. 

Table  II  gives 
measurements  and 
weights  of  standard 
four  -  cycle  engines 
built  by  the  Maschi- 
nenfabrik  Augsburg- 
Niirnburg,  while  Table 
III  gives  data  relat- 
ing to  engines  of  the 
high  speed  type. 

The  engines  given 
in  the  tables  by  no 
means  exhaust  the 
total  number  of  stan- 
dard machines.     Each 

firm  has  its  own  standards,  but  of  these  there  are  so 
many  that  it  is  almost  alwaj's  possible  to  choose  a  standard 
engine  whatever  be  the  power  required. 


y//////////////////////////A 


^ 

^ 


Fig.  81.— Outline  Drawing  of  Sulzer  Four- 
Cycle  Engines  (to  correspond  with  Table 
of  Dimensions). 


128  DIESEL  ENGINES  FOR  LAND  AND  MARINE  WORK 


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130  DIESEL  ENGINES  FOR  LAND  AND  MARINE  WORK 


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S 

IXSTALLIXG   AND   rJT'XXTXO   DIESEL   ENGINES     131 

Starting   up   the   Engine. — After   the   erection   of   tlie 
engine  is  complete  it  should  be  barred  round  by  hand,  or 
other\\ise,  several  times  by  means  of  the  barring  gear  on 
the  flywheel  which  is  provided.     The  cooUng  water  circu- 
lation has  to  be  tried,  to  ascertain  there  is  no  obstruc- 
tion to  the  flow,  and  the  engme  may  then  be  prepared  for 
starting.     It  should  be  run  if  possible  for  an  hour  or  two 
on  no  load  in  order  that  all  the  bearing  parts  of  the  machine 
may  settle  down  into  their  bearmgs,  after  which  a  load 
equivalent    to  one-quarter    or  one-half  of  the  full  output 
should  be  put  on.     Indicator  cards  can  be  taken  during 
this  time,  so  that,  if  necessary,  adjustments  may  be  made 
should  the  combustion  be  not   satisfactory.     After  shut- 
ting down,  all  the  bearings  should  be  well  examined  before 
the  engine  is  put  on  full  load,  which  may  be  done  imme- 
diately on  starting  up  again,  and  the  machine  may  be  put 
into  service   at   once.     The   only   adjustment   with  regard 
to  the  fuel  supply  which  is  at  all  Hkely  to  be  necessary  is 
in  the  event  of  one  cylinder  in  a  multi-cylinder  engine 
taking  more  or  less  than  its  proper  share  of  the  load.     Tliis 
can  be  readily  put  right  b}'  adjusting  a  small  screw  with  a 
conically  pointed  end,  which  when  screwed  into  the  fuel 
inlet  pipe  between  the  fuel  pump  and  the  pulveriser  of  any 
one  of  the  cylinders  reduces  the  supply  of  oil  to  the  pulver- 
iser, and  vice  versa.     Tliis  arrangement  is   only  adopted 
where  a  single  fuel  pump  suppHes  all  the  cyhnders,  the  oil 
being  pumped  into   a   so-called   "  distributor."     Where   a 
separate  pump  is  provided  for  each  cylinder  the  distribu- 
tion is  effected  by  means  of  a  hand  screw  on  each  pump 
which  controls  the  small  suction  valve  of  the  pump. 

The  Management  of  Diesel  Engines. — With  a  well- 
designed  and  properly  installed  Diesel  engine  no  special 
difficulties  are  to  be  encountered  in  the  operation  of  the 
machme,  which  may  be  safely  left  in  the  hands  of  an  un- 
skilled workman,  apart  from  the  overhauls,  repairs  and 
periodic  cleaning  of  the  fuel  pump  valves  ;  it  is  a  fallacy 
to  consider  that  the  cost  of  attendance  is  higher  than  with 
steam  engines — the  contrary  being  actually  the  case.     As 


132  DIESEL  ENGINES  FOR  LAND  AND  IMARINE  WORK 

with  all  internal  combustion  engines  the  water  supply  is 
one  of  the  first  considerations,  and  needs  to  be  carefully 
watched.  Thermometers  are  usually  provided  giving  the 
temperatures  of  the  jacket  water  in  each  of  the  cylinders, 
and  the  supply  of  water  can  be  separately  regulated  by 
means  of  cocks  for  each  cylinder.  The  thermometers 
however  are  more  necessary  with  a  closed  pipe  circulation 
than  with  the  ordinary  arrangement  where  the  flow  of 
water  can  be  seen,  and  this  latter  method  is  to  be  preferred 
where  circumstances  permit.  As  the  supply  of  water  is 
separate  in  each  cyHnder  jacket,  being  arranged  by  branch 
pipes  off  the  main  supply  pipe,  and  delivering  into  a  com- 
mon outlet  pipe  for  all  the  cylinders,  it  is  quite  possible 
if  there  be  an  obstruction  in  one  pipe  for  the  water  to  be 
entirely  cut  off  one  cylinder  without  interrupting  the  main 
flow.  The  only  indication  in  this  event  with  the  closed 
circuit  system  is  a  rise  in  the  temperature  of  the  jacket 
of  the  cyhnder  so  obstructed,  but  with  the  open  flow  arrange- 
ment the  stoppage  is  at  once  noted  by  the  driver.  The 
temperature  of  the  cooling  water  as  it  leaves  the  jacket  is 
best  kept  in  the  neighbourhood  of  120°  Fahr.  in  temperate 
climates,  though  it  is  perfectly  safe  to  allow  it  to  rise  to  as 
much  as  180°  Fahr.  for  a  prolonged  period.  In  Diesel 
engines  of  the  ordinary  design,  the  heat  carried  away  by 
the  jacket  water  is  usually  between  20  and  25  per  cent, 
of  the  calorific  value  of  the  fuel,  or  some  60  per  cent,  of  the 
heat  actually  converted  into  useful  work  reckoned  as 
indicated  horse  power  developed  by  the  engine.     One  H.P. 

1          •           •     1     ^   ^      33000  X    60       o  ^,,    T,mi  TT 
hour  IS  equivalent  to  =  2,544  B.Th.Us.    per 

hour,  so  that  the  heat  abstracted  by  the  jacket  water  may 
be  taken  as  2,544  X  '6  or  about  1,500  B.Th.Us.  per  hour. 
Allowing  a  temperature  rise  in  the  water  of  60°  F.  the 
quantity  required  per  hour  per  I. H.P.  developed  by  the 
engine  should  be  about  25  lb.  or  2|  gallons  per  I. H.P.  hour, 
and  the  allowance  usually  made  is  4  gallons  per  B.H.P, 
hour,  which  from  the  above  figures  is  an  ample  supply  and 


INSTALLING  AND  RUN^^ING  DIESEL  ENGINES     133 

is  indeed  never  exceeded.  Generally  the  quantity  is  con- 
siderably less  and  is  frequently  under  3  gallons  per  B.H.P. 
hour  at  full  load. 

The  perfect  combustion  of  the  fuel  oil  in  the  cyUnder 
prevents  the  valves  from  becoming  very  dirty,  but  if  the 
machine  is  run  for  a  considerable  period  without  cleaning 
the  combustion  is  not  so  good,  the  exhaust  becomes  smoky 
and  the  exhaust  valve  gets  foul  more  quickl}\  In  any 
case  it  is  preferable  to  clean  this  valve  regularly  and  as 
frequently  as  possible,  though  where  careful  attention  is 
paid  to  the  operation  of  the  engine  and  no  smoking  of  the 
exhaust  allowed,  it  is  c^uite  feasible  and  satisfactory  to  clean 
it  only  two  or  three  times  a  year.  In  most  cases  it  is  con- 
venient to  take  out  the  exhaust  valves  about  once  a  fort- 
night, and  as  the  whole  valve  and  seating  may  be  cj[uickly 
removed  and  as  quickly  replaced  by  a  spare  valve  and  seat- 
ing the  time  lost  during  the  operation  is  very  small.  The 
valve  can  then  be  cleaned  at  leisure  and  put  back  when 
the  spare  one  is  taken  out  at  the  end  of  the  next  fortnight. 
Such  frequent  cleaning  is  by  no  means  absolutely  essential 
for  the  satisfactory  operation  of  the  engine,  but  as  in  most 
installations  it  does  not  cause  the  least  inconvenience,  it 
is  to  be  recommended.  It  is,  however,  of  more  importance 
that  the  fuel  valve  should  be  cleaned  regularly,  and  cer- 
tainly once  every  fortnight  if  possible,  while  the  valves 
of  the  fuel  pumps  should  also  be  overhauled  at  the  same 
time  and  cleaned  with  oil  and,  if  necessary,  ground  on  their 
seats.  Such  attention,  which  takes  very  Uttle  time,  materi- 
ally reduces  the  running  costs,  and  frequently  minimizes 
the  cost  for  repairs. 

Owing  to  the  high  pressure  of  compression  it  is  essential 
that  all  valves  and  joints  subjected  to  the  pressure  should 
be  perfectly  tight  and  free  from  leakage.  Leakage  may 
occur  through  any  of  the  valves,  through  the  joint  between 
the  cylinder  head  and  cylinder,  or  past  the  piston,  and  of 
course  would  also  be  apparent  in  the  event  of  a  crack  devel- 
oping in  the  cyUnder.  The  effect  of  such  leakage,  which 
is  also  a  trouble  with  most  other  internal  combustion  engines, 


134  DIESEL  ENGINES  FOR  LAND  AND  MARINE  WORK 

is  to  prevent  the  necessary  high  temperature  corresponding 
to  the  top  compression  pressure  being  readied,  and  hence 
combustion  of  the  fuel  is  in  such  cases  incomplete. 

It  is  evident  that  this  state  of  affairs  will  render  it  difficult 
for  the  engine  to  maintain  its  full  power,  since  leakage  is 
a  pure  loss  of  power,  but  vdth.  a  liberally  designed  com- 
pressor it  is  always  possible  to  overcome  the  difficulty 
by  raising  the  pressure  of  the  air  used  to  inject  the  fuel 
into  the  cylinder,  though  this  necessarily  lowers  the  effi- 
ciency of  the  engine,  and  must  only  be  looked  upon  as  a 
temporary  measure.  The  exhaust  valve  is  generally  the 
most  liable  to  leak  as  it  is  subjected  to  the  severest  con- 
ditions, but  with  frequent  cleaning  not  much  trouble  is 
likely  to  be  experienced.  In  any  case  a  very  short  time 
spent  in  grinding  the  valve  upon  its  seat  will  soon  render 
it  tight.  Leakage  past  the  fuel  inlet  valve  occasionally 
takes  place,  resulting  in  too  early  ignition,  with  a  corre- 
sponding drop  of  efficiency,  as  may  be  readily  seen  on  an 
indicator  diagram,  besides  causing  a  knock  on  the  engine  ; 
and  it  is  a  good  plan,  in  order  to  avoid  this,  to  test  the  valve 
at  the  same  time  as  it  is  cleaned,  that  is  about  once  a  fort- 
night. In  the  event  of  leakage  the  valve  should  be  ground 
in,  but  occasionally  it  is  a  result  of  a  loose  valve  spindle, 
as  very  little  play  is  allowable. 

Great  care  should  be  taken  at  all  times  when  handling 
the  fuel  valve,  as  any  neglect  of  this  valve  may  result  in 
considerable  diminution  of  the  efficiency  of  the  motor, 
even  though  it  does  not  have  a  more  serious  effect.  The 
needle  {E,  Fig.  26)  should  work  easily  in  the  glands  and 
also  in  its  guide  above  the  lever  where  it  enters  into  the 
spring  casing,  and  it  should  be  gently  handled  when  taken 
out,  as  if  bent  in  a  slight  degree  it  is  liable  to  work  badly. 

The  adjustment  of  the  needle  is  usuali}^  arranged  by 
means  of  a  lock  nut  at  the  top  where  it  screws  into  or  is 
otherwise  connected  to  the  spring  spindle  above.  The 
lock  nut  should  be  marked  so  that  it  is  alwaj'S  set  back  at 
the  same  position  as  previously,  when  the  needle  is  taken 
apart,  and  when  required  the  length  of  the  needle  can  easily 


INSTALLING  AND   RUNNING   DIESEL  ENGINES     135 

be  varied  by  setting  the  lock  nut  at  a  different  angle,  so 
that  very  minute  alterations  may  be  made. 

If  the  bottom  of  the  needle  becomes  damaged  by  any 
means  and  a  cut  or  mark  of  any  sort  is  caused,  the  surface 
should  be  carefully  rubbed  with  sandpaper,  to  make  it 
smooth,  though  usually  it  is  sufficient  to  clean  with  oil. 
If  the  face  of  the  needle  has  been  altered  at  any  time,  the 
opening  of  the  valve  must  be  adjusted  before  running  the 
engine,  this  being  done  first  by  admitting  some  compressed 
air  to  the  injection  pipe  from  the  air  reservoir,  whose  valve 
however  is  immediately  closed.  The  engine  is  then  barred 
round  very  slowly,  and  the  exhaust  valve  held  open  by 
hand.  At  the  moment  when  the  fuel  inlet  valve  is  lifted 
off  its  seating  by  the  cam  and  valve  lever,  the  air  can  be 
heard  issuing  from  the  exhaust  valve,  and  the  timing  of 
the  opening  can  be  properly  adjusted  by  altering  the  lock 
nut  previously  mentioned,  so  that  the  lifting  of  the  valve 
occurs  at  the  exact  moment  required,  namely,  just  before 
the  crank  reaches  its  top  dead  centre  in  its  direction  of 
rotation,  or  in  other  words  just  before  the  piston  reaches 
the  top  of  its  stroke. 

All  the  parts  of  the  pulveriser  should  be  cleaned  with 
paraffin  and  a  small  brush,  so  that  all  the  holes  and  chan- 
nels should  be  quite  free.  It  will  not  be  found  necessary 
to  renew  the  packing  for  the  needle  at  very  frequent  inter- 
vals, provided  it  is  well  packed  in  the  first  instance,  tallow 
string  packing  being  preferable  to  any  special  composition. 

Occasionally  it  happens  that  the  needle  shows  a  tendency 
to  stick  to  the  seat,  which  may  be  caused  by  bad  combustion 
and  consequent  smokiness,  due  to  an  overload,  or  possibly 
to  the  cylinder  cover  becoming  hot,  o\Adng  to  poor  or  insuffi- 
cient circulation  of  cooling  water,  and  in  this  latter  case 
the  cooling  space  in  the  cyhnder  cover  should  at  once  be 
cleaned  out.  The  same  effect  may  also  be  produced  by 
the  injection  air  carrying  with  it  small  particles  of  matter, 
caused  hy  too  liberal  lubrication  of  the  compressor,  some 
of  the  oil  being  forced  into  the  reservoir  and  thence  to  the 
fuel  valve. 


136  DIESEL  ENGINES  FOR  LAND  AND  MARINE  WORK 

It  is  not  often  that  any  trouble  occurs  with  leakage  past 
the  piston,  as  particular  care  is  taken  in  the  construction 
of  the  rings,  but  it  may  happen  that  one  or  more  of  them 
becomes  cracked  or  broken,  when,  of  course,  replacement 
is  necessary,  this  being  the  most  troublesome  repair  that 
is  likely  to  have  to  be  made  on  a  Diesel  engine  in  the  ordin- 
ary course  of  running.  The  two  top  rings  are  subjected 
to  the  greatest  heat  and  are  the  most  liable  to  stick,  and 
hence  great  care  is  taken  in  fitting  them.  Very  little  clear- 
ance is  allowed  between  the  piston  and  cy Under  cover — 
only  about  one-third  of  that  usually  permitted  with  most 
other  internal  combustion  engines  on  account  of  the  high 
compression  pressure — and  should  this  be  diminished  to 
an  appreciable  extent  by  wear,  the  piston  rod  must  be 
lengthened  by  the  insertion  of  a  liner  of  the  requisite  thick- 
ness on  the  top  side  of  the  crank  pin  bearing.  This  is  not 
a  common  trouble,  and  is  perhaps  the  least  likely  reason 
of  imperfect  combustion,  and  a  knock  on  the  engine  is 
more  likely  to  arise  from  a  wTong  setting  of  the  cam  operat- 
ing the  fuel  inlet  valve  and  causing  it  to  open  too  early, 
while  another  possibility  is  end  play  in  the  top  or  bottom 
end  connecting  rod  bearing.  The  latter  defect  is  generally 
due  to  the  bearing  being  wrongly  fitted  in  the  first  instance, 
and  does  not  often  develop  after  the  engine  has  been  put  to 
work. 

In  any  engine, springs  may  always  be  expected  to  be  some 
source  of  trouble,  and  it  is  necessary  to  have  at  least  one 
and  preferably  more  spare  sets  for  every  spring  on  the 
machine.  As  a  matter  of  fact,  a  broken  spring  seldom 
has  any  serious  effect,  and  engines  often  run  a  considerable 
time  without  the  breakage  being  noticed,  and  in  any  case 
a  broken  spring  can  be  replaced  in  a  very  short  time. 

With  the  long  pistons  which  are  always  employed  with 
Diesel  engines  the  obliquity  of  the  connecting  rod  seems 
to  have  little  tendency  to  wear  the  cylinder  liner  oval  to 
any  extent,  and  an  80  H.P.  engine  which  the  author  gauged 
after  running  some  eight  years  showed  that  the  cyHndcr 
was  true  within  two  thousandths  of  an  inch.     With  tho 


INSTALLING  AND  RUNNING  DIESEL  ENGINES     \:i1 

excellence  of  the  design  and  manufacture  of  the  air  com- 
pressors employed  for  Diesel  engines,  in  spite  of  the  heavy 
duty  they  are  called  upon  to  perform,  no  special  precautions 
need  be  taken  in  their  operation.  The  possible  troubles 
are  those  common  to  all  machinery  of  this  class,  namely 
breaking  of  piston  rings,  and  the  springs,  but  such  occur- 
rences are  rare. 

The  lubrication  of  the  parts  of  a  Diesel  engine  needs  no 
more  than  ordinary  attention,  but  as  the  quantity  of  fuel 
oil  used  is  so  small,  the  amount  of  lubricating  oil  employed 
appears  to  be  relatively  large,  and  it  is  indeed  an  item  in 
the  cost  of  running  quite  comparable  with  the  fuel  cost, 
hence  the  supply  should  be  well  regulated.  The  small  fuel 
pumps  which  are  provided  are  arranged  so  that  the  quan- 
tity dehvered  from  the  oil  reservoir  may  be  varied  within 
a  wide  range,  and  the  difference  in  the  consumption  with 
careful  attention  is  well  worth  consideration.  With  large 
engines  the  oil  which  collects  in  the  crank  chamber  is  gener- 
ally freed  from  water  by  being  passed  through  a  filter  and 
used  over  again.  As  an  outside  figure  it  may  be  taken 
that  the  consumption  of  good  lubricating  oil  with  a  250 
B.H.P.  engine  is  about  1  gallon  for  four  hours'  running  ; 
being  lower  for  slow  speed  than  high  speed  engines,  but  of 
course  if  the  oil  is  filtered  the  total  cost  should  not  be 
debited  against  the  engine.  It  is  very  desirable,  especially 
in  the  case  of  multi-cylinder  engines,  to  take  indicator  cards 
at  not  too  widely  spaced  intervals  to  ascertain  that  each 
cylinder  is  doing  its  proper  amount  of  work,  since  it  is  quite 
possible  to  throw  a  considerable  overload  on  one  or  more 
of  the  cylinders  which  could  be  avoided  in  a  few  minutes 
were  the  fact  known,  by  altering  the  test  cocks.  More- 
over, in  installations  in  which  the  engine  is  emploj^ed  for 
a  drive  where  the  power  is  intermittent  (as  for  instance  a 
mill,  or  shafting  of  any  sort),  by  the  addition  of  machines, 
the  driving  engine  may  become  overloaded  without  the 
fact  being  apparent,  and  though  a  Diesel  engine  will  readily 
take  a  10  or  15  per  cent,  overload  for  two  or  three  hours, 
it   is  inadvisable  to    allow  this    continually,   and  it    is   a 


138  DIESEL  ENGINES  FOR  LAND  AND  MARINE  WORK 

point  of  real  economy  in  such  cases  to  provide  additional 
power. 

Cost  of  Operation  of  Diesel  Engines. — It  is,  of  course, 
always  difficult  and  sometimes  misleading  to  institute 
direct  comparisons  between  different  types  of  engines 
without  a  particular  knowledge  of  all  the  conditions  pre- 
vailing, but  it  is  at  the  same  time  possible  to  take  a  general 
view  of  the  advantages  to  be  derived  in  certain  common 
cases,  more  especially  as  there  is  at  the  present  time  a  large 
amount  of  data  relating  to  actual  results  which  cannot 
be  refuted.  At  sea,  as  is  shown  later,  there  may  be  many 
reasons  for  the  employment  of  Diesel  or  other  oil  engines 
apart  from  the  question  of  economy,  but  on  land  that  is 
not  the  case,  and,  speaking  generally,  the  success  of  the 
Diesel  engine  for  this  work  must  depend  entirely  on  the 
reduction  in  total  running  costs  it  can  show  in  comparison 
with  steam  and  gas  engines.  The  question  is  obviously 
not  merely  one  of  fuel  economy,  since  there  are  a  host  of 
other  considerations  which  come  into  play,  and  were  it 
solely  a  matter  of  the  cost  of  the  oil  consumed,  in  compari- 
son with  the  cost  of  the  coal  used  with  gas  and  steam  engine 
plant,  the  adoption  of  the  Diesel  engine  would  of  necessity 
become  almost  universal.  Capital  cost,  however,  must 
always  be  an  important  consideration,  and  this  also  exer- 
cises a  considerable  effect  upon  the  annual  running  costs 
owing  to  the  necessary  allowance  which  has  to  be  made 
for  interest  and  depreciation  on  the  plant,  and  as  at  the 
present  time  a  Diesel  engine  is  dearer  than  either  a  steam 
engine  with  boiler  and  accessories,  or  a  suction  gas  plant, 
this  point  puts  the  former  at  a  certain  disadvantage,  though 
the  difference  is  relatively  small.  In  all  new  installations,  and 
also  frequently  in  additions  to  existing  ones,  the  question  of 
space  occupied  by  the  plant  becomes  of  importance  inas- 
much as  suitable  buildings  have  to  be  constructed  for  the 
accommodation,  and  where  the  land  is  of  high  value,  which 
is  often  the  case,  the  expense  involved  in  acquiring  this 
makes  the  question  an  even  more  urgent  one.  In  this 
matter  the  Diesel  engine  has  the  advantage,  since  it  is  much 


INSTALLING  AND  RUNNING  DIESEL  ENGINES     139 

cjmaller  for  the  same  power  tlian  a  steam  or  gas  plant,  and 
in  many  instances  where  additional  power  is  required,  and 
extension  of  premises  is  impossible,  the  question  of  the 
type  of  engine  to  be  employed  solves  itself  automatically 
in  favour  of  the  Diesel  motor. 

Though  on  land,  reliability  of  operation  is  not  usually 
of  the  same  vital  importance  as  at  sea  owing  to  spare  power 
commonly  being  available,  it  frequently  happens  that 
perfect  freedom  from  any  possibility  of  breakdown  is  the 
deciding  factor,  and  that  a  stoppage  of  but  a  few  hours' 
duration  may  nullify  the  whole  advantage  of  very  much 
decreased  running  costs.  It  is  for  this  reason  that  new 
types  of  machinery  are  so  long  in  finding  general  adoption 
in  spite  of  the  undoubted  economies  the}^  are  capable  of 
effecting  until  they  have  passed  through  long  periods  of 
satisfactory  operation.  After  the  wide  experience  of  the 
last  sixteen  years  with  Diesel  engines  this  point  can  no 
longer  be  said  to  weigh  against  them,  and  it  is  now  ad- 
mitted that  in  reliability  they  are  quite  equal  to  the  best 
class  of  steam  engine,  and  rather  superior  to  gas  engines. 
There  is  further  the  important  point  to  be  remembered 
that  a  Diesel  engine  is  practically  self-contained,  whereas 
with  the  gas  and  steam  engines  there  are  the  producer 
and  boiler  respectively  to  be  considered  as  possible  sources 
of  failure,  besides  some  auxiliaries  which  are  unnecessary 
with  Diesel  engines.  The  next  point  which  has  to  be  con- 
sidered is  the  cost  of  attendance  and  repairs,  and  it  is  well 
known  that  this  item  may  easily  reach  a  figure  comparable 
with  the  fuel  bill.  This  question  is  really  dependent  on 
the  last,  and  the  fact  that  the  Diesel  engine  is  a  reliable 
and  simple  machine  naturally  reacts  on  the  amount  which 
has  to  be  expended  annually  on  wages,  renewals,  etc.,  which 
is  relatively  small,  and  may  with  safety  be  put  at  not  more 
than  three-quarters  of  that  allowed  for  steam  and  gas  engines. 
In  fact  this  figure  is  very  conservative,  as  may  be  under- 
stood when  it  is  remembered  that  stokers  for  the  boilers 
or  producers  may  be  dispensed  with  entirely,  and  it  has 
generally  been  found  that  two-thirds  is  a  more  relative 


140  DIESEL  ENGINES  FOR  LAND  AND  MARINE  WORK 

estimate.  The  amount  to  be  apportioned  in  any  esti 
mate  for  renewals  and  repairs  is  always  difficult  to  deter- 
mine, as  there  are  such  wide  variations,  but  there  are  many 
actual  instances  where  this  cost  is  but  a  few  pounds  per 
annum  for  large  Diesel  engines.  There  are  certain  advan- 
tages which  should  not  be  lost  sight  of  in  any  comparison 
between  engine  types,  but  which  cannot  readilj^  be  expressed 
in  money  value,  though  their  importance  is  great.  There 
is  the  question  of  standby  losses  which  always  enters  into 
consideration,  and  may  cause  a  large  addition  to  fuel  costs, 
more  particularly  in  the  case  of  steam  engines,  and  to  a 
lesser  extent  with  gas  engines,  that  is  to  say,  losses  pro- 
duced in  the  generating  portion  of  the  plant  (the  boiler  or 
gas  producer)  when  the  engine  itself  is  not  running.  In 
a  Diesel  engine  these  are,  of  course,  absolutely  non-existent, 
since  the  machine  may  be  started  up  at  a  moment's  notice 
immediately  it  is  required.  Another  point  of  importance 
is  the  fact  that  in  the  large  majority  of  installations,  engines, 
during  the  greater  portion  of  their  operation,  run  at  a  com- 
paratively low  load  factor,  that  is  to  say,  generate  a  power 
much  below  their  normal  (and  consequently  most  effi- 
cient) output.  In  a  steam  engine  the  efficiency  falls  very 
considerably  ^^ith  a  decrease  of  the  load,  and  in  a  gas  engine 
the  variation  is  very  marked  though  not  so  serious.  In 
a  Diesel  engine,  on  the  other  hand,  the  difference  per  B.H.P. 
hour  at  full  load  and  at  half  or  even  quarter  is  relatively 
small,  as  may  be  seen  from  the  following  figures  of 
consumption  which  most  manufacturers  guarantee  with 
cyhnders  of  80  H.P.  and  upwards. 

•42  lb.  per  B.H.P.  hour  at  full  load. 

•45  ,,       ,,  ,,  „  three-quarters  load. 

•50  ,,       ,,  ,,  ,,  half  load. 

•31   ,,       ,,  ,,  ,,  quarter  load. 

The  following  figures  which  are  given  regarding  the  run- 
ning costs  of  Diesel  engines  must  not  be  taken  too  definitely 
as  applj'ing  to  every  case,  but  they  give  a  fair  idea  of  what 
may  be  expected  in  ordinary  installations.     The  size  of  the 


INSTALLING  AND   RUNNING   DIESEL   ENGJNES     Ml 

plant  naturally  makes  some  considerable  dilTcrence,  though 
not  so  much  as  with  other  engines  for  reasons  given 
above,  while  the  nearer  the  annual  load  factor  approaches 
unity  the  lower  becomes  the  cost  of  running  per  B.H.P. 
hour. 

Considering  an  engine  of  200  B.H.P.  running  for  300 
days  in  the  year  an  average  of  15  hours  per  day  at  a  load 
factor  throughout  of  60  per  cent.,  the  number  of  B.H.P. 
hours  per  annum  w^ould  be  300  X  15  x  200  x  -6  =  540,000, 
The  fuel  consumption  may  be  taken  at  0-5  lb.  per  B.H.P. 
hour,  which  from  the  guarantee  figures  given  above  is  a 
high  estimate,  and  with  the  price  of  crude  petroleum  at 

455.  per  ton  the  cost  of  fuel  would  be  £ '■ x  2i 

^  2,240  ^ 

=  £270  per  annum.  The  wages  for  the  attendants  would 
be  about  £200,  while  general  maintenance  and  repairs  may 
be  estimated  at  £50,  and  waste,  water,  stores  and  sundries 
at  another  £20.  Good  lubricating  oil  for  Diesel  engines 
can  be  purchased  at  Is.  3d.  per  gallon,  and  the  quantity 
consumed  by  such  an  engine,  assuming  that  it  is  not  filtered 
and  used  over  again,  w^ould  be  in  the  neighbourhood  of  2 
to  3  gallons  per  day,  according  to  the  care  exercised  by 
the  attendant,  and  the  annual  cost  may  be  put  at  £50. 
The  cost  of  a  Diesel  engine,  including  erection,  foundations 
and  setting  to  work,  varies  at  the  present  time  from  £8  to 
£11  per  B.H.P.,  being  dependent  on  the  size,  type  (high  or 
low  speed,  two  or  four  cycle),  the  cost  of  foundations,  acces- 
sibility of  site,  and  other  considerations,  but  for  the  pur- 
poses of  estimate  may  be  taken  as  £10  per  B.H.P.,  or  £2,000 
for  the  engine  in  question.  Making  the  usual  allowance 
of  10  per  cent,  for  interest  and  depreciation  on  the  plant, 
an  amount  of  £200  per  annum  has  to  be  added  to  the 
3'early  running  costs,  which  may  then  bo  summarized  as 
follows  ; — 


142  DIESEL  ENGINES  FOR  LAND  AND  MARINE  WORK 

Estimate  of  Annual  Working  Costs  of  200  B.H.P.  Diesel 
Engine  Running  4,500  Hours 


Fuel  oil  at  45^.  per  ton 

Wages  for  attendants   . 

Maintenance  and  repairs    . 

Waste,  water,  stores,  etc    . 

Lubricating  oil  . 

Interest  and  depreciation  on  plant 


Total 
£ 

270 

Per  B.H.P.  hr. 
}3once. 
012 

200 

0089 

50 

0022 

20 

0009 

50 

0022 

200 

0089 

Total     ....   £790         . .  0-351(i. 

Omitting  interest  and  depreciation,  the  working  costs 
aggregate  to  £590  per  annum  or  0'26fZ.  per  B.H.P.  liour,  and 
this  figure  may  be  relied  upon  as  Hkely  to  cover  by  far  the 
larger  number  of  cases  met  with  in  ordinary  practice,  while 
in  big  installations  an  overall  cost  of  0'25d.  per  B.H.P.  hour, 
including  interest  and  depreciation  charges,  maybe  assumed 
as  correct.  In  four  installations  with  which  the  author 
is  familiar,  in  none  of  which  does  the  annual  load  factor 
rise  above  30  per  cent.,  the  yearly  working  costs,  excluding 
interest  and  depreciation,  amount  respectively  to  0-26fZ., 
O'Sld.,  0-2 kZ.  and  0'23d.  per  B.H.P.  hour,  or  an  average 
of  0'2ofZ.  for  the  four  plants,  the  period  over  which  the  costs 
were  reckoned  being  in  no  case  less  than  six  months. 

Although  in  the  matter  of  economy  the  Diesel  engme 
shews  more  particularly  to  advantage  in  the  smaller  sizes, 
that  is  to  say,  up  to  about  1,500  B.H.P.,  now  that  the 
manufacture  of  very  large  engmes  has  become  a  practical 
proposition,  it  is  interestmg  to  note  how  motors  up  to  4,000 
B.H.P.  can  be  shewn  to  compare  favourably  with  the  most 
efficient  modern  steam  turbmes. 

The  following  data  are  based  upon  an  actual  case  and 
refer  to  an  mstallation  of  2,500  K.W.  miits,  considering 
Diesel  enguies  in  the  one  case  and  steam  turbines  in  the 
other.  The  Diesel  motor  is  of  the  two-cycle  smgle-actmg 
type,  running  at  a  normal  speed  for  this  size  of  about  130 
revolutions   per   minute.     The   estimates   are   based   on   a 


INSTALLING  AND   RUNNING  DIESEL  ENGINES   143 

year's  working  assuming  an  actual  running  period  of  G,000 
hours  per  annum,  and  an  average  load  on  the  generator 
of  2,000  K.W.  The  eost  of  fuel  oil  is  taken  at  BOs.  per  ton, 
and  of  coal  at  155.  per  ton. 

Considering  first  the  capital  costs,  and  omittmg  switch- 
board and  cables,  etc.,  although  the  Diesel  set  is  more 
expensive,  there  is  a  substantial  saving  in  the  cost  of  build- 
ings, and  the  figures  work  out  as  follows — 

£ 
2,500  K.W.  Diesel  generating  set  with  all  necessary  acces- 
sories       25,000 

Engine  room,  foundations,  etc.,  including  cost  of  site  .        5,000 


Total  cost  of  Diesel  plant       ......  30,000 

2,500  K.W.  Turbo-generator  with  condensing  i:)lant,  boilers  £ 

and  accessories         .......  13,000 

Engine  and  boiler  house,  foundations,  chimney,  etc.,  includ- 
ing cost  of  site        .......  13,000 


Total  cost  of  steam  plant       ......      26,000 

The  approximate  annual  running  costs  in  the  two  cases 
are  as  under  : — 

Diesel  Set. — ^The  consumption  of  oil  with  a  Diesel  motor 
of  this  size  is  about  0-45  lb.  per  B.H.P.  hour,  or  with  an 
alternator  of  ordinary  efficiency  about  0-66  lb.  per  K.W. 
hour.  The  lubricating  oil,  which  is  admittedly  an  expensive 
factor  with  Diesel  engines,  may  be  taken  at  0  01  lb. per  K.W. 
hour,  although  the  builders  would  probably  guarantee  a 
lower  figure  if  necessary.  The  cost  of  suitable  oil  is  about 
Is.  6d.  per  gallon. 

With  regard  to  cooling  water  a  good  deal  depends  on 
the  circumstances,  but  in  the  case  in  question,  sea  water 
was  available  at  a  total  cost  of  kl.  per  1,000  gallons.  The 
amount  required  is  about  6  gallons  per  K.W.  hour,  but  for 
piston  cooling,  fresh  water  is  necessary,  about  H  gallons 
per  K.W.  hour  being  the  quantity.  This  would  of  course 
be  recooled  in  a  cooling  tower,  and  only  the  usual  10  per 
cent,  make  up  losses  need  be  reckoned  upon. 


144  DIESEL  ENGINES  FOR  LAND  AND  MARINE  WORK 

Calculating  on  this  basis,  the  total  cost  becomes  : — 

£ 

.      8,850 


Cost  of  fuel 


2,000  X  6,000  X  -66  x  2'5 


2,240 
Cost  of  attendance  ;   four  men  and  one  foreman  at  an  average 

of  £2  per  week         .... 
Water  for  jackets  and  pistons 
Lubricating  oil,  etc.         .... 
Repairs  and  maintenance  at  1  per  cent. 
Interest  and  depreciation  at  10  j^er  cent. 


520 
200 

1,000 
250 

2,500 


£13,320 


Steam  Plant. — A  steam  turbo-generating  set  of  2,500 
K.W.  has  a  consumption  of  15  lb.  of  steam  (superheated) 
per  K.W.  hour,  or  allowing  30  per  cent,  stand-by  losses, 
and  an  evaporation  of  7  lb.  of  steam  per  pound  of  coal,  the 
quantity  of  coal  per  K.W.  hour  at  an  average  load  of  2,000 
K.W.,  is  2-8,  which  is  5,600  lb.  per  hour,  or  15,000  tons 
per  annum. 

The  amount  of  condensing  water  necessary  is  some  1 50,000 
gallons  per  hour,  or  900  million  gallons  per  annum,  for 
which  the  total  cost  of  pumping  may  be  taken  at  Jc?.  per 
1,000  gallons  as  before.  The  following  gives  the  overall 
estimate  : — 


Cost  of  coal  =  15,000  tons  at  155. 

Cost  of  attendance  ;    6  men  and  1  foreman  at  an  average  of 

£2  per  week.  .... 

Condensing  and  feed  water     . 
Lubricating  oil,  etc.        .... 
Repairs  and  INIaintenance  at  1  per  cent. 
Interest  and  depreciation  at  10  per  cent. 


£ 
11,250 

730 

2,000 

250 

135 

1,350 

£15,715 


The  saving  with   the  Diesel  set  thus  amounts  to   about 
£2,400  or  more  than  15  per  cent.,  and  it  will  be  noticed 


INSTALLING  AND   RUNNING  DIESEL  ENGINES    145 

that  no  allowance  has  been  made  for  depreciation  of  build- 
ings, which  item  would  greatly  favour  the  Diesel  equipment. 
The  respective  costs  per  K.W.  hour  are  0-314  <Z,  for  the 
steam  plant,  and  0-2Gd.  for  the  Diesel  driven  set. 


CHAPTER  V 
TESTING  DIESEL  ENGINES 

OBJECT  OF  TESTING — TEST  ON  200  B.H.P.  DIESEL  ENGINE  — 
TEST  ON  300  B.H.P.  HIGH  SPEED  MARINE  ENGINE — TEST 
ON  500  B.H.P,  ENGINE — TEST  ON  HIGH  SPEED  DIESEL 
ENGINE, 

Object  of  Testing. — -The  working  of  Diesel  engines  is  so 
regular,  and  the  efficiency  is  such  a  predetermined  factor, 
that,  generally  speaking,  such  elaborate  tests  of  fuel  con- 
sumption as  are  usual  with  steam  plants,  are  not  essential, 
and  there  is  very  seldom  any  question  of  the  guarantee 
being  exceeded.  The  majority  of  Diesel  engines  supplied 
for  land  work  are  for  the  purpose  of  driving  dynamos,  either 
direct  or  through  a  belt,  and  hence  most  tests  are  made  on 
the  combined  set,  when,  as  with  steam  dynamo  plants,  it 
is  convenient  to  express  the  fuel  consumption  in  pounds 
per  kilowatt  hour.  The  efficiency  of  the  dynamo  is  readily 
obtained  separately,  so  that  the  actual  brake  horse  power  of 
the  engine  is  at  once  determined,  and  hence  a  test  on  a  direct 
coupled  set  is  in  every  way  satisfactory,  and  is  more  conveni- 
ent than  a  brake  test,  especially  for  large  engines.  Though 
the  main  object  of  all  engine  testing  from  a  commercial 
point  of  view  must  be  to  obtain  the  actual  cost  of  running 
the  machine  at  its  various  loads,  or  in  other  words  the 
amount  of  fuel  it  consumes  per  H.P.  hour,  much  other  useful 
and  interesting  information  may  be  obtained.  The  calorific 
value  of  the  fuel  oil  used  in  Diesel  engines  differs  very  con- 
siderably, and  though  this  has  little  effect  from  the  com- 
mercial aspect,  since  the  oil  of  lower  heating  value  is  gener- 
ics 


TESTING   DIESEJ.   ENGINES  147 

ally  cheaper,  and  thus  though  more  oil  may  be  used  the  cost 
is  approximately  the  same.  An  ordinarily  complete  test 
on  a  Diesel  engine  should  aim  at  producing  the  following 
results  :  The  normal  output,  and  overload  capacity  of  the 
engine  ;  the  fuel  consumption  per  I.H.P,  and  per  B.H.P. 
hour  at  various  loads  ;  the  mechanical  efficiency  ;  the  quan- 
tity of  cooling  water  required  with  a  desirable  rise  of  tempera- 
ture (usually  60°  F.)  ;  and  the  heat  account  to  determine  the 
respective  amounts  of  heat,  (1)  converted  to  useful  work, 
(2)  carried  away  in  the  jacket  water,  and  (3)  dispelled  in  the 
exhaust  gases. 

The  amount  of  lubricating  oil  is  of  importance,  but  this 
can  hardly  be  obtained  with  any  degree  of  accuracy  in  a 
short  test  and  is  best  noted  over  a  week's  run  ;  as  a  Diesel 
engine  uses  much  more  oil  when  starting  up  than  in  ordin- 
ary operation,  the  amount  should  never  be  gauged  from  a 
trial  on  the  testing  bed.  The  instruments  and  appHances 
necessary  for  such  a  test  are  neither  elaborate  nor  expensive. 
The  fuel  consumed  may  be  measured  by  weight  or  by  volume 
provided  its  specific  gravity  be  accurately  determined.  The 
temperatures  of  the  jacket  waters  for  each  cylinder  (in  a 
multi-cylinder  engine)  are  obtained  from  thermometers, 
placed  in  thermometer  pockets,  one  in  each  cylinder  head 
just  at  the  water-outlet,  and  a  common  thermometer  for  aU 
cylinders  in  the  supplj^  pipe  to  give  the  temperature  of  the 
inlet  water.  The  temperature  of  the  exhaust  gases  is  regis- 
tered on  a  high  reading  thermometer  fixed  in  the  exhaust 
pipe  as  near  the  cylinders  as  possible,  and  all  these  thermo- 
meters, except  for  the  exhaust  gases  and  the  inlet  cooling 
water,  are  employed  under  ordinary  working  conditions 
and  need  not  be  special  for  the  test.  The  weight  of  the 
jacket  cooling  water  can  be  conveniently  found  by  deliver- 
ing it  alternately  into  measuring  tanks  of  known  capacity  as 
with  the  common  arrangement  for  estimating  the  quantity 
of  condensed  water  from  a  steam  engine,  or  the  feed  water 
entering  the  boiler  in  a  steam  engine  or  boiler  test  respec- 
tively. Indicator  cards  have  to  be  taken  frequently  and 
simultaneously  off  each  cylinder,  which  is  provided  with 


148  DIESEL  ENGINES  FOR  LAND  AND  MARINE  WORK 

indicator  cocks  and  operating  gear  for  this  purpose.  The 
indicators  employed  may  be  of  the  ordinar}^  Crosby  or  simi- 
lar type  and  indicator  pistons  and  springs  are  commonly 
used  in  which  a  pressure  of  about  400  lb.  per  sq.  inch  is  repre- 
sented by  a  compression  of  1  inch,  a  common  arrangement 
with  Continental  engines  being  one  in  which  a  pressure  of  1 
kilogram  per  sq.  centimetre  gives  a  movement  of  the  indica- 
tor pencil  of  0-8  millimetre.  The  calorific  value  of  the  oil 
has  to  be  obtained,  and  this  may  be  done  in  a  special  calori- 
meter in  which  combustion  takes  place  with  oxj^gen  under 
high  pressure.  The  calorific  value  may  also  be  determined 
by  analysis  of  the  fuel  into  its  three  main  constituents, 
carbon,  hydrogen  and  sulphur — the  oxj^gen  and  nitrogen 
being  negligible  quantities — and  multiplying  the  weight  of 
each  of  these  elements  by  the  respective  known  calorific 
values  of  each  element,  and  adding  to  obtain  the  resultant 
calorific  value,  though  this  method  is  not  perfectly  satis- 
factory. The  figures  for  carbon,  hydi'ogen,  and  sulphur  are 
respectively  about  15,540,  52,000,  and  4,500  B.Th.Us.  per 
pound.  The  heat  passing  away  in  the  exhaust  gases  can  be 
determined  from  a  knowledge  of  the  weight  of  exhaust  gas, 
its  specific  heat  at  constant  pressure  and  the  excess  of 
temperature  over  that  of  the  atmosphere. 
Let  t     =  the  difference  in  temperature  between  the  exhaust 

gases  and  the  atmosphere. 
V   =  volume  swept  through  by  the  piston  in  cubic  feet 

in  one  stroke. 
w   =  weight  of  one  cubic  foot  of  air  at  atmospheric 

pressure  and  temperature. 
Kp  =  s]3ecific  heat  of  air  at  constant  pressure. 
W  —  weight  of  fuel  consumed  per  revolution  of  the 

engine. 
The  weight  of  fuel  and  air  entering  the  cylinder  (for  a  single 
cj'linder  four-cj'cle  engine)  per  revolution  is  |  V^^  +  W,  and 
hence  the  heat  rejected  to  the  exhaust  is  (|  Yw  +  W)  K^^ 
B.Th.U.  per  revolution  of  the  engine.  This  method,  though 
giving  a  sufficiently  accurate  result  for  most  purposes  is  not 
exact  because  the  temperature  of  the  air  when  the  cylinder  is 


TESTING  DIESEL  ENGINES  149 

full  is  above  the  atmospheric  temperature  to  a  degree  which 
cannot  be  easily  determined.  If  closer  results  are  required 
an  analysis  of  the  exhaust  gases  must  be  made  by  collect- 
ing samples  and  testing  them  in  an  Orsat  or  similar  appara- 
tus. From  the  relative  quantities  of  nitrogen  and  oxygen 
in  the  exhaust  gases,  the  excess  of  air  admitted  to  the  engine 
over  that  required  for  combustion  ma}^  be  obtained.  From 
the  analysis  of  the  oil  the  weight  of  air  needed  for  complete 
combustion  may  be  obtained  from  the  equivalent  combining 
weights  of  air  (or  rather  the  oxygen  in  it)  with  carbon, 
hydrogen,  and  sulphur.  By  multiplying  the  weight  so 
obtained  by  the  ratio  of  the  air  drawn  into  the  cylinder  to 
that  used  during  combustion  the  actual  weight  of  air  taken 
into  the  cylinder  per  pound  of  oil  is  obtained,  and  the 
remaining  calculations  are  as  before. 

Diesel  engines  run  so  regularly  and  with  so  little  variation 
in  any  way,  that  comparatively  short  tests  are  quite  satis- 
factory and  reliable  so  long  as  frequent  readings  are  taken 
to  enable  reasonable  checks  to  be  made  against  personal 
errors  in  measurements.  Indicator  cards  should  be  taken 
every  five  minutes  or  quarter-hour,  dependent  on  the  duration 
of  the  trial,  and  as  mentioned  before,  these  are  to  be  taken 
on  all  the  c^dinders  of  an  engine  simultaneously,  even  if  this 
necessitates  two  or  more  operators,  since  it  is,  of  course, 
impossible  to  rely  on  all  the  engines  doing  equal  work  or 
that  the  indicated  power  does  not  vary  in  the  short  interval 
of  time  elapsing  while  a  man  taking  the  indicator  cards 
moves  from  one  cock  to  another.  The  power  developed  by 
the  dynamo  is  ascertained  in  the  usual  manner  with  a  tested 
ammeter  and  voltmeter,  and  the  work  done  in  driving  the 
air  compressor  may  be  obtained,  if  desired,  by  taking  indi- 
cator cards  of  the  pump  cylinders,  and  if  the  compressors  are 
separately  driven,  as  is  sometimes  the  case,  the  power 
absorbed  by  the  motor  has  also  to  be  noted. 

In  the  following  pages  descriptions  and  results  of  tests  on 
Diesel  engines  by  well-known  authorities  are  given,  and  these 
may  well  be  taken  as  a  basis  in  conducting  similar  tests. 
Some  of  them  were  made  with  varying  loads  on  the  engine, 


150  DIESEL  ENGINES  FOR  LAND  AND  MARINE  WORK 

and  trials  under  such  conditions  are  frequently  necessary, 
and  in  any  case  valuable,  as  most  plants  operate  for  a  com- 
parative large  proportion  of  their  life  at  less  than  the  full 
load,  and  hence  the  results  on  normal  load  do  not  always 
represent  the  working  conditions  of  the  engine. 

Test  on  a  200  B.H.P.  Diesel  Engine.— This  test  was 
made  by  Herrn  Chr.  Eberle,  and  described  in  a  paper  read 
before  the  Baj^erischer  Revisions  Verein,  on  a  200  B.H.P. 
Diesel  four-cj'cle  slow  speed  single  acting  engine  of  two  cyhn- 
ders  coupled  direct  to  a  continuous  current  generator.  The 
test  was  made  under  working  conditions  after  the  engine  had 
been  installed.  The  diameter  of  the  cylinder  is  430  mm. 
(16-9  inches)  and  the  piston  stroke  G80  mm.  (26-8  inches), 
while  the  normal  speed  of  rotation  is  160  revolutions  per 
minute.  The  engine  is  provided  with  a  flywheel  on  each  side 
of  the  cylinders ;  and  there  are  two  two-stage  air  compressors, 
one  driven  off  each  connecting  rod.  The  consumption  of 
fuel  was  obtained  by  emplojing  an  open  reservoir  connected 
by  piping  to  the  fuel  pump,  the  test  being  started  at  the 
moment  the  oil  in  the  reservoir  reached  a  definite  point  as 
indicated  by  a  gauge  glass.  The  oil  in  the  reservoir  was 
kept  up  to  its  original  level  by  replenishing  from  a  small  can, 
containing  a  loiown  weight  of  oil,  and  tests  were  rejected  if 
any  of  the  intermediate  readings  varied  by  more  than  2' 
per  cent.  The  power  developed  by  the  cylinders  was  ob- 
tained by  taking  frequent  indicator  cards,  and  cards  were 
also  obtained  from  the  air  compressors.  The  speed  was 
noted  every  minute,  and  the  pressure  in  the  compressors 
was  taken.  The  oil  fuel  was  tested  and  found  to  have  a 
calorific  value  of  9,813  calories,  which  corresponds  to  17,660 
B.Th.U.,  and  the  specific  gravity  of  the  oil  was  0-893.  In 
Table  IV  the  chief  figures  and  deduced  data  are  given,  but 
as  the  quantity  of  cooling  water  was  not  measured,  a  detailed 
heat  account  could  not  be  obtained,  though  the  exhaust  gases 
were  analysed  in  an  Orsat  apparatus.  It  is  to  be  noticed 
that  the  speed  of  the  engine  varied  between  164*5  and  159-9 
from  no  load  to  overload,  a  difference  of  only  2-8  per  cent., 
the  respective  indicated  powers  being  46-4  and  298-4  I.H.P. 


TESTING  DIESEL  ENGINES 


151 


At  normal  full  load  the  final  pressure  in  the  air  pump  cylin- 
der from  the  diagrams  was  61  atmospheres,  and  the  com- 
bined indicated  H.P.  for  the  two  cylinders  of  one  pump  was 
6-82  I. H.P.  or  13'64  I.H.P.  for  the  two  pumps,  assuming 
them  to  be  doing  equal  work.  The  temperature  of  the 
exhaust  gases  varies  considerably  with  the  load,  being  131°  C. 
at  no  load  and  466°  C.  when  the  engine  is  developing  its 


t«^ 


250 

\ 

200 

\ 

^ 

"■"—•J 

. 1             _p 

/n5 

inn 

sn 

so 


200 


100  150 

Brake    Horse  Power. 

Fia.   82. — Curve  showing  Fuel  Consvimption. 


250  B. H.P. 


maximum  power.  The  consumption  of  fuel  at  the  various 
loads  is  shown  graphically  in  Fig.  82,  the  difference  from  half- 
load  to  full  load  being  comparatively  small.  As  showing 
the  constancy  of  the  fuel  consumption  with  Diesel  engines, 
four  machines  of  similar  type  and  construction  were  tested 
together,  when  it  was  found  that  the  respective  amounts  of 
oil  used  per  B.H.P.  hour  were  185-0,  189-9,  189-7  and  190-4 
grams. 

Test  on  300  B.H.P.  High  Speed  Marine  Engine.— 
This  test  was  carried  out  by  Herrn.  Chr,  Eberle,  on  a  300 


152  DIESEL  ENGINES  FOR  LAND  AND  MARINE  WORK 


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TESTING  DIESEL  ENGINES 


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154  DIESEL  ENGINES  FOR  LAND  AND  MARINE  WORK 


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TESTING  DIESEL  ENGINES  155 

B.H.P.  four-cylinder  foiir-cj'Cle  engine,  wiiich  at  its  normal 
output  was  designed  for  a  speed  of  400  revolutions  per 
minute.  The  engine  is  totally  enclosed  and  the  cranks  are 
set  at  180°  ;  a  vertical  two  stage  air  compressor  mounted  on 
the  end  of  the  bed-plate  and  driven  direct  off  the  crank  shaft 
serves  for  the  air  supply  to  all  the  cjdinders.  The  four  fuel 
pumps  are  arranged  together  in  the  front  of  the  engine  and 
are  all  driven  off  the  horizontal  cam  shaft.  Forced  lubrica- 
tion is  of  course  adopted,  and  two  small  lubricating  pumps 
are  driven  direct  off  the  end  of  the  crank  shaft,  the  oil  being 
cooled  after  passing  through  the  bearings,  etc.,  and  used 
over  again.  Two  other  small  pumps  are  also  driven  off  the 
crank  shaft  for  the  circulation  of  the  cooling  water  both  for 
the  cylinders  and  for  the  exhaust  pipe,  which  was  jacketed 
in  this  engine.  Being  intended  for  ship  propulsion  the 
machine  is  not  provided  with  a  governor,  but  has  a  safety 
regulator  to  prevent  the  engine  running  away.  The  weight 
of  the  engine,  including  the  starting  vessels  and  all  pumps, 
was  only  about  10  tons,  while  a  similar  slow  speed  engine 
would  weigh  something  over  50  tons.  This  is  equivalent 
to  30  H.P.  per  ton  weight,  which  is  extremely  high. 

In  the  tests  the  engine  was  coupled  direct  to  a  continuous 
current  generator,  which  was  loaded  as  required  on  a  resist- 
ance, and  the  power  measured  by  a  tested  ammeter  and 
voltmeter  in  the  usual  way.  The  engine  was  run  at  various 
speeds  between  about  250  and  500  revolutions  per  minute, 
the  variation  being  obtained  by  controlhng  the  amount  of 
fuel  entering  the  cylinders  by  means  of  a  lever.  The  tests 
carried  out  were  as  follows  : — 

(1)  With  normal  admission  of  fuel  and  speeds  of  250,  300, 
and  500  revolutions  per  minute.     (Tests  1  to  6  in  Table  Y.) 

(2)  With  half  normal  admission  and  speeds  of  250,  300, 
400  and  500  revolutions  per  minute.  (Tests  7  to  10  in 
Table  V.) 

(3)  With  maximum  admission  and  speeds  of  400  and  500 
revolutions  per  minute.     (Tests  11  and  12  in  Table  V.) 

The  efficiency  of  the  dynamo  was  carefully  determined  for 
each  speed  and  output  by  running  it  at  the  various  speeds  at 


loG  DIESEL  ENGINES  FOR  LAND  AND  MARINE  WORK 


no  load,  whence  all  the  losses  were  calculated  and  the 
efficiencies  obtained.  These  are  included  in  the  table,  but 
the  figures  from  which  they  are  deduced  are  omitted.  The 
oil  consumption  was  obtained  by  taking  the  supply  direct 
from  a  vessel  "with  a  gauge  glass,  and  at  the  beginning  and  end 
of  each  test  the  level  of  the  oil  in  the  vessel  was  arranged  to 
be  at  the  same  point  as  indicated  on  the  gauge  glass,  the 
consumption  being  made  up  by  adding  an  accurately  weighed 


100  200  300 

Brake  Horse  Power 

Fig.  83. — Curve  showing  Fuel  Consumption, 


400B.H.P. 


amount  of  oil  as  required,  and  by  this  means  intermediate 
check  readings  could  be  taken. 

The  cooling  water  was  passed  through  measuring  tanks 
and  its  quantity  determined,  and  the  temperatures  at  the 
inlet  and  outlet  as  well  as  that  of  the  exhaust  gases  were 
registered  by  mercury  thermometers.  In  Fig.  83  the  fuel 
consumptions  are  represented  graphically  under  all  the  con- 
ditions of  the  tests,  and  show  remarkably  constant  results. 
At  about  250  revolutions  perminute  the  consumption  was  189 


TESTING   DIESEL   ENGINES  157 

grams.,  at  300  revolutions  per  minute  192  grams.,  and  at  400 
revolutions  per  minute  196'5  grams,  per  B.H.P.  hour.  Be- 
tween the  working  limits  for  which  the  engine  was  designed, 
namely  250  to  400  revolutions  per  minute,  with  normal  fuel 
admission  the  difference  w-as  only  189-5  to  196'5,  or  about  4 
per  cent.,  this  being  readily  accounted  for  by  the  greater 
power  for  the  compressor.  Even  for  speeds  up  to  500 
revolutions  per  minute  the  variation  was  less  than  7  per 
cent.,  excluding  the  trial  at  this  speed  wdth  partial  admission. 
In  test  No.  6,  where  a  consumption  of  211  grams,  per  B.H.P. 
hour  is  sho^vn,  there  was  an  obstruction  in  one  of  the  fuel 
pipes,  and  hence  the  cylinder  it  fed  worked  uneconomically, 
and  vitiated  the  result  which  should  therefore  be  neglected. 
From  the  results  in  Tests  Nos.  1  to  5,  vrith  the  engine  on  its 
normal  load,  it  is  seen  that  the  heat  employed  in  doing  useful 
work  varies  between  31  to  33  per  cent. — the  heat  carried 
away  by  the  cooling  water  is  33  to  34  per  cent.,  w^hile  23 
to  25  per  cent,  is  rejected  in  the  exhaust  gases.  The  last 
figure  is  rather  low,  while  that  for  the  cooling  water  is 
high,  which  is  accounted  for  by  the  fact  that  a  large 
amount  of  water  was  used,  varying  from  5  to  over  6  gallons 
per  B.H.P.  hour,  whereas  the  quantity  usually  allowed  is 
little  more  than  3  gallons  per  B.H.P.  hour  ;  probably  also 
the  exhaust  pipe  was  w^ater  cooled. 

Herr  Eberle  makes  the  following  comments  on  the  tests  : — 

(1)  The  engme  works  from  250  to  500  revolutions  per 
minute,  with  varying  admissions,  and  develops  from  100  to 
400  H.P.  with  perfect  combustion,  and  without  any  trouble 
in  operation. 

(2)  The  change  from  one  speed  to  another  is  easily  and 
rapidly  effected  by  the  movement  of  a  single  lever. 

(3)  The  average  fuel  consumption  for  all  powers  and 
speeds  is  little  if  any  different  from  that  of  slow  speed 
engines. 

(4)  The  mechanical  efficiency  is  equal  to  that  of  slow  speed 
engines. 

(5)  The  lubrication  is  good,  and  during  a  twelve  hours' 
run  no  heating  was  observed  in  any  part  of  the  machine. 


158  DIESEL  ENGINES  FOR  LAND  AND  MARINE  WORK 

Tests  on  500  B.H.P.  Engine. — The  following  is  a  slightly 
abbreviated  account  of  a  complete  test  carried  out  by  JNIr. 
IMichael  Longridge,  on  a  three-cylinder  slow  speed  four-stroke 
engine  manufactured  by  Messrs.  Carels,  Freres,  of  Ghent  ^ : — 

The  engine  was  a  three-crank  inverted  vertical,  with  three 
single  acting  cylinders  numbered  54,  55,  and  56,  No.  54 
being  above  the  idle  end  of  the  crank  shaft.  Each  cyhnder 
was  22-05  in.  (560  mm.)  diameter,  with  a  piston  stroke  of 
29'53  in.  (750  mm.).  The  normal  speed  was  150  revolutions 
per  minute. 

The  valves  were  placed  in  the  cylinder  covers  as  usual, 
and  were  actuated  by  levers  driven  by  cams  on  a  horizontal 
shaft,  which  in  turn  was  driven  by  a  vertical  shaft  and  bevel 
gear  from  the  idle  end  of  the  crank  shaft.  The  cylinders, 
cylinder  covers,  and  exhaust  valves  were  water  cooled, 
but  the  pistons  were  not. 

The  engine  drove  a  d3'namo  carried  upon  a  prolongation 
of  the  crank  shaft. 

The  air  for  pulverr^ing  the  oil  and  spraying  it  into  the 
cj'linders  was  compressed  in  an  independent  pair  of  three 
stage  vertical  air  compressors  worked  by  a  two-throw  crank 
shaft,  belt  driven  by  a  motor  receiving  current  from  the 
dynamo  upon  the  engme  crank  shaft.  The  air  compressors, 
therefore,  though  essential  to  the  working  of  the  engine, 
were  not  in  this  case  parts  of  the  engine,  and  in  calculating 
the  mechanical  efficiency  of  the  engine  from  the  dynamo 
output  and  the  indicator  diagrams  this  fact  should  not  be 
lost  sight  of.  Had  the  compressors  been  driven  direct  1}^  by 
the  engine  the  difference  between  the  work  put  into  the 
dynamo,  which  is  the  brake  horse-power,  and  the  indicated 
horse-power  would  have  been  increased  by  the  power 
required  to  compress  the  air. 

The  areas  of  the  compressor  pistons  were  : — 

102-40  sq.  in.  (660-5  sq.  cm.). 

32-30  sq.  in.  (208-1  sq.  cm.). 

8-79  sq.  in.  (5675  sq.  cm.). 

^  Annual  Report  of  British  Engine,  Boiler,  and  Electrical  In- 
surance Co.,  Ltd. 


TESTING   DIESEL  ENGINES  159 

and  the  stroke  7087  in.  (180  mm.),  the  speed,  when  com- 
pressing to  about  64  atmospheres,  being  about  160  revolu- 
tions per  minute. 

The  dynamo  was  twelve-pole,  continuous  current,  shunt 
wound,  by  Lahmeyer  &  Co.,  rated  to  give  450  kilowatts  at 
550  volts  when  running  at  150  revolutions  per  minute.  The 
eflSciencies  given  by  the  makers  are  : — 

At 112  kw.  225  kw.  337  kw.  450  kw.  562  kw. 

Efficiency  about     .       -88  -925  -935  -91  -935 

and  these  figures  have  been  adopted  in  calculating  the 
brake  horse  power  of  the  engine  corresponding  to  the 
measured  output  of  the  d^'namo. 

The  power  was  absorbed  by  iron  wire  resistance  coils, 
and  the  load  regulated  by  appropriate  switches. 

The  motor  for  driving  the  air  compressors  was  six-pole, 
shunt  wound,  continuous  current,  by  the  same  makers, 
rated  to  give  75  B.H.P.  at  630  revolutions  per  minute. 

The  calculated  efficiencies  given  by  the  makers  are  : — 

At  .  .  Full  load.  Three-quarter  load.  Half-load.  Quarter -load. 
Efficiency       90-5  ..  89  ..  86        . .        76-5  m. 

Four  trials  were  made,  the  results  ef  which  are  sho^^•n  on 
the  accompanj'ing  Tables. 

The  first,  a  preliminary  trial,  intended  to  be  at  full  load 
but  actually  a  little  low,  the  second  at  full  load,  the  third  at 
half  load,  and  the  fourth  with  no  external  load,  the  engine 
driving  the  air  compressors  only,  and,  of  course,  the  dynamo 
and  motor  which  transmitted  the  power  to  them. 

With  respect  to  the  figures  in  the  Table,  the  following 
explanations  should  be  read  : — 

Line  4. — The  diameter  of  the  cylinder  of  No.  56  engine 
was  gauged.  The  diameters  of  the  other  two  were  taken 
from  the  drawing. 

Line  6. — The  revolutions  were  recorded  by  an  engine 
counter,  and  the  speed  indicated  by  a  tachometer. 

Line  7. — The  water  for  the  jackets  was  supplied  from  the 
to^vn's  main,  and  measured  through  a  water  meter  which  was 
said  to  have  been  recent Iv  calibrated. 


160  DIESEL  ENGINES  FOR  LAND  AND  BL^RINE  WORK 

Line  9. — The  discharge  pipes  from  the  jackets  were  con- 
ducted to  a  common  pipe  discharging  into  a  drain.  The 
same  thermometer  was  used  for  measuring  the  temperature 
of  inlet  and  discharge. 

Line  11. — The  temperature  of  the  exhaust  was  measured 
close  to  the  engine  by  a  mercury  thermometer  passing  through 
a  gland  in  the  exhaust  pipe,  with  compressed  nitrogen 
above  the  mercury  to  prevent  the  latter  boiling. 

All  these  observations  were  taken  at  intervals  of  ten 
minutes. 

Line  12. — The  gas  samples  were  collected  and  analysed 
by  Professor  Van  de  Velde,  of  Ghent. 

Line  13. — The  oil  used  was  from  Galicia.  There  is  con- 
siderable doubt  about  the  calorific  value  of  the  oil.  A  sample 
taken  at  the  lime  of  the  trial,  and  analysed  by  Professor 
Van  de  Velde,  gave  : — 

Carbon 84  81  per  cent. 

Hydrogen 14-78 

Sulphur 0  17 

99-76  per  cent. 
and  therefore  had  a  calorific  value  by  calculation  of  : — 
•8481  X  14,540  +   -1478  x  52,000  +  -0017  X  4,000  = 
20,049  B.T.U. 
As  the  Professor  made  no  calorimeter  test,  a  sample  was 
sent  over  to  England  in  March,  and  tested  by  Mr.  C.  I 
Wilson,  who  gave  the  calorific  value  as  10,120  calories,  or 
18,220  B.T.U.     Owing  to  the  great  discrepancy  between 
the  two  results,  and  to  the  improbably  high  efficiency  of  the 
engine   resulting   from   the   adoption   of   the   latter   value, 
another  sample  was  sent  to  England  in  May  and  analysed 
and  tested  by  Dr.  Boverton  Redwood,  who  gave  the  follow- 
ing figures  : — 

Carbon 83-17  per  cent. 

Hydrogen 11-56         ,, 

Sulphur 0-36 

Oxygen,  nitrogen,  etc.,  by  difference  .      .  4-91         „ 

100-00 


TESTING   mESEL  ENGINES 


161 


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162  DIESEL  ENGINES  FOR  LAND  AND  MARINE  WORK 


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TESTING  DIESEL   ENGINES  163 

Calorific  value,  10,897  calories  or  19,600  B.T.U.,  which  is 
somewhat  higher  than  that  calculated  from  the  analysis 
viz.  : — 

•8317  X  14,540  +   -1156  x  52,200  +  -0036  X  4,000  = 
18,144  B.T.U.  per  lb. 

As  Professor  Van  de  Velde's  analysis  was  made  from  a 
sample  taken  at  the  trial,  and  it  is  confirmed  by  Dr.  Red- 
wood's test,  it  has  been  inserted  in  the  heat  account.  The 
adoption  of  Mr.  Wilson's  value  of  18,220  B.T.U.  would  make 
the  thermal  efficiency  of  the  engine  about  50  per  cent., 
which  is  so  much  above  the  efficiency  obtained  with  smaller 
engines  that  the  writer  caimot  accept  it  without  further 
confirmation.  (The  author  may  here  remark  that  it  is 
never  satisfactory  in  estimating  the  efficiency  of  an  engine 
to  rely  upon  the  heating  value  of  the  oil  as  obtained  by 
calculatio7b.) 

Line  14. — To  weigh  the  oil  used,  a  small  tank  fitted  with 
a  cock  near  the  bottom  was  placed  on  a  weighing  machine. 
The  tank  was  first  partly  filled  with  oil  from  a  tap  in  the  oil 
main  above  it.  It  was  then  accurately  balanced  by  weights 
in  the  scale  pan.  A  single  weight  of  2  kilos,  was  then  added 
to  the  weights  in  the  scale  pan  and  oil  run  into  the  tank  till 
the  lever  of  the  machine  floated.  The  2-kilo.  weight  was  then 
taken  out  of  the  scale  pan  and  the  cock  at  the  bottom  opened 
to  allow  the  oil  to  run  into  a  second  tank  which  fed  the 
engine  until  the  lever  again  floated.  The  surface  in  the 
feed  tank  at  the  beginning  of  each  trial  was  marked  by  its 
contact  with  a  sharp-pointed  gauge,  and  was  brought  to  the 
same  level  before  a  fresh  supply  was  run  in  from  the  weigh- 
ing tank.  Except  at  the  preliminary  trial  on  the  13th, 
when  there  was  some  trouble  with  one  of  the  pipe  con- 
nexions which  required  the  writer's  attention,  the  times  when 
the  surface  of  the  oil  in  the  measuring  tank  touched  the 
point  of  the  gauge  were  accurately  taken  so  that  the  rates 
of  consumption  might  be  recorded. 

The  leverage  of  the  machine  (1  to  10)  and  the  2-ldlo.  weight 
used  for  weighing  20  kilos,  of  oil  were  tested  with  new  accurate 


1G4  DIESEL  ENGINES  FOR  LAND  AND  ]\IARINE  WORK 

weights,  and  were  found  to  be  practicali}'  correct,  2  kilos,  in 
tho  scale  pan  balancing  2,00G  grammes  on  the  machine. 
The  writer  has  described  the  method  of  weighing  the  oil  at 
length  to  remove  any  doubts  about  its  accuracy  which  might 
be  raised  by  the  figures  in  the  heat  account  of  Trial  III.i 

Lines  17-19. — The  mean  effective  pressures  were  calculated 
from  indicator  diagrams  taken  at  intervals  of  15  minutes. 
The  indicators  used  were  on  cylinders  Nos.  54  and  55,  two 
Crosby's,  and  on  cylinder  No.  56,  an  ElKott  Simplex.  The 
cords  connecting  the  indicator  to  the  motion  were  only  about 
2  feet  long.  It  will  be  seen  that  the  mean  pressures  in  the 
different  cyhnders  differed  considerably. 

Line  21. — The  output  of  the  dynamo  was  measured  by  an 
ammeter  and  voltmeter  belonging  to  Messrs.  Carols,  which 
had  been  calibrated  before  the  trial.  The  readings  of  both 
instruments  were,  moreover,  checked  throughout  by  a 
Weston  set  in  the  circuit,  which  w^as  itself  checked  at  the 
Manchester  Technical  School  before  and  after  the  trials. 

To  afford  some  check  upon  the  dynamo  efficiencies  given 
by  the  makers,  the  C^R  losses  in  the  armatvire  and  magnet 
coils  and  in  the  shunt  regulator  were  measured.  With  the 
full  load  of  350  kilowatts  these  were  as  follows  : — 

C^R  loss  in  armatiire  brushes,  etc 8-9  kw. 

,,  .,       shunt  coil 3-0    „ 

,,         ,j       shunt  regulator  resistance    .      .      .       2-5    „ 


14-4  kw. 

Assuming  the  iron  losses  and  friction  (which  could  not 
be  measured)  to  be  equal  to  the  above,  the  total  losses  would 
amount  to  about  28-8  kw.,  giving  an  efficiency  of  92*4,  as 
against  93 -5  claimed  by  the  makers. 

Lme  22. — ^The  brake  horse-power  given  in  this  Ime  is  at 
each  load  the  measured  output  of  the  dynamo  in  horse-power 
divided  by  the  coefficient  of  efficiency  given  by  the  makers 
for  that  load.  As  already  explained,  it  includes  the  power 
absorbed  by  the  motor  and  air  compressor,  and  is  therefore 
higher  than  it  would  have  been  had  the  air  compressor  been 

1  The  heat  account  has  been  omitted, 


TESTING  DIESEL  ENGINES  165 

driven  by  levers  and  links  from  one  of  the  piston-rod  cross- 
heads,  or  by  an  eccentric  or  crank  from  the  engine  crank 
shaft,  as  under  ordinary  circumstances  it  woukl  be. 

Lines  22  and  23. — From  the  preceding  paragraph  it  will 
be  understood  that  the  horse-power  absorbed  by  the  engine 
itself  is  less  and  the  mechanical  efficiency  greater  than  if 
the  air  compressor  had  been  driven  directly  by  the  engine. 

Lines  27  and  28  give  the  kilowatts  suppUed  to  the  motor 
which  drove  the  air  compressors  and  the  horse-power  given 
out  by  it. 

Line  29. — The  figure  36  H.P.  in  the  first  column  was 
arrived  at  by  indicating  the  cylinders  of  one  of  the  air  com- 
pressors when  compressing  to  about  60  atmospheres  and 
assuming  that  diagrams  from  the  cylinders  of  the  other 
compressor  would  have  to  be  of  the  same  areas.  The  differ- 
ence of  8-8  H.P.  between  this  JBgure  and  the  figure  44-8  in 
the  first  column  of  line  28  represents  the  power  absorbed 
b}^  the  driving  belt  and  the  mechanism  of  the  compressors. 

The  figures  in  columns  2,  3,  and  4  of  Une  29  are  put  dowTi 
on  the  assumption  that  the  fractional  loss  of  8-8  H.P.  was 
constant  at  all  loads. 

Line  31. — If  the  compressors  had  been  driven  by  the 
engine,  the  power  absorbed  would  probably  have  been  less 
than  indicated  by  the  figures  in  line  28  and  more  than 
shown  in  Une  29.  Assuming  that  it  would  have  been  half-way 
between  the  two, 

Lines  31  and  32  show  approximately  what  the  brake 
horse-power  and  mechanical  efficiencies  of  the  engine  would 
have  been  had  the  compressor  formed  part  of  the  engine ;  and 

Line  33  gives  approximately  the  probable  oil  consump- 
tion  per  brake  horse-power-hour  with  tliis   arrangement. 

The  high  percentage  of  heat  unaccounted  for  on  the  second 
trial  may  be  due  to  imperfect  combustion,  especially  during 
the  early  part  of  the  trial,  when  for  a  short  time  there  was  a 
httle  smoke  from  No.  56  cjdinder,  and  the  excess  of  heat 
accounted  for  on  the  third  trial  is  most  likeh'  due  to  over- 
estimation  of  the  weight  of  the  exhaust  gases.  This  weight 
varies  inversely  as  the  percentage  of  CO 2  in  the  gases,  and 


1G6  DIESEL  ENGINES  FOR  LAND  AND  MARINE  WORK 

any  leakage  of  air  into  the  gas  samples  reduces  this  percentage 
and  consequently  unduly  increases  the  calculated  weight 
of  the  gases. 

The  conditions  during  the  first  three  trials  were  not 
constant. 

During  the  two  full  load  trials  the  temjDerature  of  the 
exhaust  and  of  the  discharge  from  the  jackets  continued 
to  rise  for  some  time  after  commencement  of  each  trial, 
while  during  the  half-load  trial  both  temperatures  feU. 
The  inference  is  that  during  the  earlier  parts  of  the  first  two 
trials  the  temperature  of  the  cylinder  walls  and  pistons  was 
increasing  by  absorption  of  the  heat  from  the  gases,  and 
during  the  third  was  falling  by  imparting  heat  to  the  gases. 
To  show  the  effect  of  these  exchanges  of  heat,  heat  accounts 
have  been  calculated  for  the  periods  during  which  the  tem- 
perature conditions  were  fairly  constant.  As  wiU  be  seen 
by  these  accounts,  the  effect  upon  the  oil  consumptions  and 
thermal  efficiencies  was  practically  negligible. 

As  already  explained  on  page  140,  the  line  showing  the 
rate  of  oil  consumption  in  this  first  trial  is  only  approxi- 
mately correct,  as,  omng  to  a  little  difficulty  in  running  the 
oil  from  the  measuring  tank  into  the  feed  tank  it  was  not 
possible  always  to  bring  the  level  in  the  latter  up  to  the 
point  gauge  before  running  in  a  fresh  weighing. 

The  rise  in  temperature  of  the  water  from  the  jackets 
up  to  4.45  p.m.  was  due  to  an  insufficient  supply.  The 
supply  was  then  increased. 

The  sudden  rise  in  the  temperature  of  the  exhaust  at  5.40 
is  unaccountable. 

On  the  14th,  the  engine  ran  with  full  load  from  6  a.m.  till 
breakfast  time,  and  then  with  about  half-load  till  just  before 
the  beginning  of  the  trial.  It  attained  its  normal  tempera- 
ture soon  after  the  trial  began.  The  speed  was  increased 
soon  after  starting  to  stop  the  smoke  from  No.  56  cylinder. 

As  it  was  intended  to  make  a  half-load  and  no-load  trial, 
and  also  to  examine  the  valves  and  piston  of  one  of  the 
cylinders,  the  half-load  trial  was  begun  almost  immediately 
the  full-load  trial  was  finished. 


TESTING  DIESEL  ENGINES  167 

The  last,  or  no-load  trial,  was  not  started  till  half  an  hour 
after  the  end  of  the  half-load  trial.  No  gas  analysis  was 
taken  during  this  trial. 

The  engine  worked  well  during  the  trials,  except  that 
there  was  a  little  smoke  with  the  full  load.  The  smoke  came 
from  No.  56  cyUnder,  which,  as  may  be  seen  from  the  line  17 
of  the  Table,  was  doing  more  than  its  fair  share  of  the  work. 

After  the  full-load  trial  on  the  14th,  the  whole  of  the  load 
was  suddenly  thrown  off.  The  speed  increased  from  163 
revolutions  per  minute  to  164  revolutions  per  minute,  and 
settled  to  157  revolutions  per  minute. 

Tests  on  a  High  Speed  Diesel  Engine. — It  is  of  impor- 
tance to  determine  the  extent  to  which  the  piston  speed,  or 
what  is  the  same  thing,  the  speed  of  revolution  of  a  high 
speed  Diesel  engine,  can  be  increased  to  obtain  greater  powers 
with  the  same  diameter  of  cylinder.  The  expression  for 
the  indicated  horse-power  of  a  four-cycle  single  acting  engine 
is  : — 

I.H.P.  =  i  P-^^  ^-       (1) 

33000 

where  P  =  Average  indicated  pressure  in  lb.  per  sq.  inch. 
L  =  Stroke  of  piston  in  feet. 

TT 

A  =  Area  of  piston  in  sq.   inches  =  —  d-  where 

d  =  cylinder  diameter. 

N  =  Revolutions  of  engine  per  minute. 

This  formula  may  be  expressed  otherwise  as  : — 

PAS 
I.H.P.  =  '^•^•^-    (2) 

2200 

where  S  =  piston  speed  in  feet  per  second. 

From  formula  (2)  it  appears  that  with  the  same  cylinder 
diameter  the  I.H.P.  may  be  increased  either  by  the  employ- 
ment of  a  higher  mean  pressure  or  by  an  increase  of  piston 
speed,  and  Dr.  Seiliger  made  an  important  series  of  tests  ^ 
to  ascertain  the  limits  to  which  these  means  could  be  carried. 

*  Zeitschrift   des  Vereins  doutscher  Ingenieure,   1911. 


1C8  DIESEL  ENGINES  FOR  LAND  AND  MARINE  WORK 

If  Q   =  Theoretical  quantity  of  air  drawn  in  the  cylinders 
per  hour  in  cub.  ft. 
K   =  Ratio  of    actual  quantity  of    air  to  theoretical 

quantity. 
c     =  Consumption  of  oil  per  I.H.P.  hour  in  lb. 
Qi    =  Minimum  quantity  of  air  required  for  the  com- 
bustion of  1  lb.  of  fuel  in  c.f. 
Then  KQ  must  not  be  less  than  QiC  X  I.H.P. 

and  Q=LxAx  —  X cub.  ft. 

2         144 

hence  K.L.A.  —    X  ■ — -  must  not  be  less  than  QiC  X  f 


2         144                                                      33000 
or  P  must  not  be  greater  than  13,750  (3) 

From  this  it  is  seen  that  the  mean  pressure  is  dependent 
on  the  value  K  and  the  fuel  consumption  per  I.H.P.  hour. 
In  the  tests  which  were  carried  out  on  a  high  speed  engine 
of  300  B.H.P.  normal  output  it  was  found  that  both  these 
values  were  in  turn  dependent  on  the  piston  speed,  and  that 
therefore  increased  power  could  not  be  obtained  indefinitely 
in  a  cylinder  of  constant  diameter  b}"  direct  increase  of 
piston  speed  or  mean  pressure.  The  results  of  the  tests 
may  be  stated  as  follows  : — 

1.  The  fuel  consumption  per  I.H.P.  hour  decreases  with 
the  speed  of  revolution,  when  the  mean  pressure  remains 
constant. 

2.  The  fuel  consumption  per  I.H.P.  hour  decreases  with 
the  mean  pressure  when  the  speed  of  revolution  remains 
constant. 

3.  The  temperature  of  the  exhaust  gases  decreases  with 
the  speed  of  revolution  when  the  mean  pressure  remains 
constant. 

4.  The  temperature  of  the  exhaust  gases  decreases  with 
the  mean  pressure  when  the  speed  of  revolution  remains 
constant. 

5.  The  power  absorbed  by  the  air  pump  is  directly 
proportional  to  the  speed  of  the  engine  but  independent 
of  the  mean  pressure. 


TESTING  DIE8EL  ENGINES 


169 


6.  The  power  absorbed  in  friction,  etc.,  increases  with  the 
speed  of  revolution,  and  also  with  an  increase  in  the  mean 
pressure. 

7.  The  value  K  decreases  with  an  increase  of  speed  and  is 
independent  of  the  mean  pressure. 

All  these  important  facts  can  be  deduced  theoretically 
and  bear  out  the  results  of  the  tests.  It  will  be  seen  from 
(7)  that  K  decreases  as  the  speed  rises,  i.e.  K  varies  inversely 
with  S,  though  not  in  the  same  ratio,  and  similarly  from  (1) 
the  fuel  consumption  per  I.H.P.  hour,  c  rises  with  an 
increase  in  the  piston  speed.  The  value  of  the  mean  pres- 
sure P  from  formula  (3)  is  dependent  on  the  ratio  —  and  if 

the  speed  rises  this  ratio  decreases  and  hence  P  falls.  The 
product  PS  on  which  the  output  of  the  engine  depends, 
with  the  same  cylinder  diameter,  therefore  tends  to  become 
constant  at  higher  speeds,  or  in  other  words,  increase  of 
speed  of  revolution  above  a  certain  point  will  not  produce  a 
useful  increase  in  output.  This  was  well  instanced  in 
Seihger's  tests,  as  is  shown  in  the  following  table. 


Speed  of  Revolu- 

Piston Speed  in- 

Per- 

Output of 

Per- 

tion  increased 

creased  meters 

centage 

engine 

centage 

r.p.m. 

per  see. 

Increase. 

increased. 

Increase. 

frora                  to 

from                   to 

B.H.P. 

300 

350 

3-8 

4-43 

17% 

41 

16% 

350 

400 

4-43 

501 

15% 

10 

3% 

306 

401 

30 

4-8 

33% 

76 

33% 

401 

493 

4-8 

6 

25% 

30-5 

10% 

These  results  show  clearly  the  distinct  limitations  to 
the  output  of  a  Diesel  engine  of  fixed  diameter  of  cylinder 
and  that  by  mere  increase  of  speed  of  revolution  (or  piston 
speed)  the  power  developed  by  the  motor  cannot  be  usefully 
increased  beyond  a  certain  point,  and  that  for  every  engine 
there  is  a  value  for  the  product  of  the  piston  speed  and  the 
mean  pressure  which  gives  most  efficient  results. 


CHAPTER    VI 
DIESEL  ENGINES  FOR  MARINE  WORK 

GENERAL  CONSIDERATIONS — ADVANTAGES  OF  THE  DIESEL 
ENGINE  FOR  MARINE  WORK — DESIGN  AND  ARRANGE- 
MENT OF  DIESEL  MARINE  ENGINES — METHODS  OF  REVERS- 
ING DIESEL  ENGINES AUXILIARIES  FOR  DIESEL  SHIPS — 

HORSE  POWER  OF  MARINE  DIESEL  ENGINES WEIGHTS  OF 

MARINE      DIESEL      ENGINES — THE      DESIGN      OF     LARGE 
ENGINES. 

General  Considerations. — ^The  question  of  the  employ- 
ment of  internal  combustion  engines  for  the  propulsion  of 
ships  has  received  a  large  amount  of  attention  during  recent 
years,  since,  in  fact,  the  gas  engine  reached  its  present  high 
degree  of  economy  and  perfection.  This  is  not  remarkable 
in  view  of  the  much  higher  efficiency  to  be  obtained  by  the 
gas  engine  than  with  the  steam  engine,  and  when  the  use 
of  coal  for  the  operation  of  gas  engines  became  possible  by 
the  intermediary  of  gas  producers,  the  question  of  driving 
ships  with  gas  engines  seemed  likely  to  assume  practical 
shape.  For  various  reasons  very  little  has  up  to  the  present 
been  done  in  this  direction,  and  briefly  it  may  be  said  that 
the  potential  advantages  to  be  gained  by  the  employment 
of  suction  gas  engines  for  ships  are  not  sufficient  to  warrant 
the  departure.  In  the  first  place  the  advantage  of  economy 
in  the  cost  of  operation  is  not  very  marked,  since,  though  a 
large  amount  of  work  has  been  carried  out  with  the  object 
of  developing  a  satisfactory  producer  working  on  bituminous 
coal,  it  may  be  taken  that  anthracite  would  have  to  be 
employed  at  any  rate  to  guarantee  sufficient  reliability 
of  operation  for  marine  work.  The  relative  prices  of 
anthracite  and  the  bunker  coal  used  with  steam  engines  at 
once  largely  minimize,  if  they  do  not  entirely  destroy,  the 

170 


DIESEL  ENGINES  FOR  MARINE   WORK         171 

economy  in  fuel  costs  with  gas  engines.  Owing  to  the  neces- 
sity of  the  producer,  a  gas  installation  saves  little  or  nothing 
in  space  or  weight,  as  compared  with  the  steam  plant,  and 
firen^en  are  required  for  the  producer  or  for  the  boiler, 
though  of  course  the  same  attention  is  not  required,  but  in 
any  case  the  reduction  in  the  number  of  attendants  would 
be  small.  Furtlier  a  satisfactorily  reversible  gas  engine  is  at 
present  hardly  an  accomphshed  fact,  and  speed  variation 
is  a  difficult  problem  ;  taking  all  matters  into  consideration, 
therefore,,  it  is  safe  to  say  the  adoption  of  gas  engines  for 
the  propulsion  of  ships  is  not  hkely  to  make  much  headway 
in  the  future,  although  there  may  be  one  or  two  isolated 
instances  in  which  a  certain  measure  of  success  may  be 
obtained. 

It  is  apparent  that  provided  an  oil  engine  could  be  pro- 
duced which  is  equal  to  a  steam  engine  in  reliabihty,  it 
would  have  many  points  of  superiority  as  compared  vdih 
the  gas  engine  while  retaining  all  the  general  advantages  of 
the  internal  combustion  engine.  Hence  the  Diesel  engine, 
which  has  proved  itself  more  efficient  than,  and  at  least 
as  serviceable  as,  the  gas  engine  for  land  work,  seems 
to  be  eminently  adaj)ted  for  the  propulsion  of  ships,  but 
there  have  naturally  been  many  difficulties  to  overcome 
before  it  could  be  in  a  position  to  compare  with  the  steam 
engine,  in  matters  which  for  marine  work  are  of  perhaps 
greater  importance  than  mere  economy.  A  marme  engine 
must  before  everything  be  absolutely  reliable,  and  with  the 
present  day  perfection  of  the  steam  engine,  resultant  upon 
nearly  a  century  of  practical  experience,  it  is  easy  to  see 
that  the  Diesel  engine  had  to  make  much  progress  and  to 
pass  through  a  long  period  of  trial  under  the  severest  con- 
ditions of  operation  in  practice  before  it  could  seriously  be 
considered  as  a  satisfactory  motor  for  marine  propulsion. 
After  some  seventeen  years,  during  ^hich  the  engine  has  been 
employed  for  all  manner  of  stationary  work,  with  a  reh- 
ability  now  generally  agreed  to  be  equal  to  that  of  the  steam 
engine,  it  may  with  reason  be  said  that  this  probationary 
period  has  expired.     At  the  same  time,  it  must  be  admitted 


172  DIESEL  ENGINES  FOR  LAND  AND  MARINE  WORK 

that  marine  practice  is  in  many  ways  different  from  stationary 
operation,  and  though  this  point  should  not  be  exaggerated, 
as  marine  engineers  are  apt  to  make  it,  there  is  no  doubt 
that  the  conditions  of  ser\dce  at  sea  are,  in  general,  much 
more  severe  than  on  land.  It  was  necessary,  therefore, 
that  before  the  Diesel  engine  could  hope  to  find  ready  adop- 
tion for  large  vessels,  experience  should  be  gained  with  its 
use  on  smaller  boats,  so  that  a  reasonable  idea  as  to  its  reH- 
ability  and  general  suitability  for  ships  could  be  obtained. 
There  are  at  the  present  time  some  500  vessels  of  various 
types  propelled  by  Diesel  engines,  and  many  have  been 
running  for  some  years.  Most  of  these  are  quite  small  boats 
and  there  are  included  a  number  of  submarines,  but  the 
figure  itself  is  sufficient  to  show  that  the  introduction  of  the 
Diesel  engine  even  in  large  ships  cannot  really  be  considered 
an  innovation,  but  only  a  sHght  advance  on  an  already 
proved  arrangement.  Moreover  the  Diesel  marine  engine, 
excepting  only  the  type  employed  on  submarines,  where  a 
relatively  large  number  of  cylinders  is  a  necessity,  differs 
but  slightly  from  the  stationary  motor,  since  reversing  and 
speed  regulation  are  modifications  which  involve  no  material 
alterations  in  design,  and  the  experience  gained  with  the 
land  engines  is  thus  in  a  measure  equivalent  to  that  which 
would  have  had  to  be  obtained  at  sea  were  the  construction 
different  in  any  marked  degree. 

Advantages  of  the  Diesel  Engine  for  Marine  Work. — 
The  advantages  of  the  Diesel  engine  for  marine  propulsion 
over  the  steam  plant  are  in  no  sense  problematical  but  can 
be  reduced  to  monetary  saving  in  running  costs,  or  increased 
earning  capacity.  The  reduction  in  fuel  cost  must  neces- 
sarily be  dependent  on  the  prices  of  oil  and  coal,  and  is  a 
matter  that  can  readily  be  determined  by  the  shipowner, 
since  the  fuel  that  will  be  consumed  with  a  Diesel  motor 
ship,  with  engines  of  any  particular  power,  can  be  guaran- 
teed within  the  narrowest  limits,  while  the  coal  burned  in 
the  same  ship  propelled  by  steam  engines  can  readily  be  fixed 
in  the  light  of  past  experience. 

The  amount  of  coal  which  is  consumed  in  steam  engine 


DIESEL  ENGINES  FOR  MARINE  WORK         173 

propelled  ships  per  H.P.  naturally  varies  considerably  with 
the  class  of  vessel,  and  the  tj'-pe  and  power  of  the  machin- 
ery, and  also  with  the  quality  of  coal  burned  ;  this  latter 
point  should  be  remembered  in  any  comparison  of  the  costs  of 
coal  and  oil,  since  where  cheap  coal  is  used  the  amount  is 
usually  increased,  and  average  figures  for  consumption  then 
do  not  form  an  accurate  basis.  In  fact  the  only  really  fair 
method  of  estimation  of  fuel  consumption  is  one  in  which 
the  calorific  value  is  taken  into  account.  An  average  taken 
over  a  very  large  number  of  vessels  now  in  operation,  par- 
ticularly those  between  3,000  and  5,000  tons  displacement, 
of  which  the  bulk  of  the  world's  shipping  is  composed,  gives 
as  the  consumption  of  coal  per  I.H.P.  hour,  1'55  lb.,  and 
assuming  a  mechanical  efficiency  of  85  per  cent. — brake 
horse-power  to  indicated  horse-power — the  figure  of  1'8  lb.  of 
coal  per  B. H.P.  is  obtained.  As  a  matter  of  fact  an  enormous 
number  of  vessels  consume  very  much  more  fuel  than  this, 
2  lb.  per  B.H.P.  hour  being  a  common  figure  for  smaller 
vessels,  but  on  the  other  hand  in  certain  cases  the  consump- 
tion is  less,  and  1-8  may  be  taken  as  a  fair  average.  The 
larger  sizes  of  Diesel  engines  now  being  built  by  many  firms, 
are  usually  guaranteed  not  to  require  more  than  0-4  lb.  of 
crude  oil  per  B.H.P.  hour,  while  the  actual  consumption  is 
frequently  as  low  as  0*37  lb.  The  two-cycle  engine  is,  as 
previously  stated,  sHghtly  less  efficient  than  the  four  cycle, 
and  for  purposes  of  comparison  it  may  be  assumed  that  0*45 
lb.  of  fuel  is  required  per  B.H.P.  hour  with  a  marine  Diesel 
engine. 

On  this  basis  it  will  be  seen  that  in  a  ship  propelled  with 
Diesel  engines  the  consumption  of  fuel  should  be  approxi- 
mately one-quarter  of  the  weight  of  coal  burned  with  a  steam 
engine  plant,  but  in  reality  the  saving  may  be  much  gi'eater. 
When  running  at  reduced  speeds  the  Diesel  engine  is  rela- 
tively more  eflScient  than  the  steam  engine.  This  point  is 
of  particular  importance  for  war  vessels,  which  for  by  far 
the  greater  portion  of  the  time,  run  at  much  below  their 
full  power  and  speed,  while  the  same  remark  applies  to 
trawlers  and  similar  vessels,  and  even  ships  which  make 


174  DIESEL  ENGINES  FOR  LAND  AND  MARINE  WORK 

long  voyages  nominally  at  full  speed,  frequently  have  to 
slow  down  for  many  hours  on  end  for  various  reasons. 
The  matter  need  not  be  emphasized  too  strongly,  but  it 
is  certainly  one  of  the  features  of  the  Diesel  engine  which 
distmguishes  it  from  all  other  prime  movers  which  have 
been  employed  for  marine  propulsion,  including  the  gas 
engme.  With  steam  engines  and  particularly  steam  tur- 
bines the  efficiency  at  low  powers  is  undoubtedly  j)oor,  in 
spite  of  the  many  methods  which  have  been  devised  to 
improve  it. 

There  are  of  course  no  stand-by  losses,  which  may  be 
an  important  point  in  steamships  making  frequent 
calls  at  ports.  The  question  of  auxiliaries  enters  largely 
into  the  matter  of  fuel  consumption,  as  may  be  well 
understood  from  the  fact  that  the  power  required  for 
the  auxiharies  is  some  20  to  25  per  cent,  of  that  developed 
by  the  propelling  engines.  Steam-driven  auxiharies 
are  notoriously  inefficient,  and  a  considerable  saving  may 
be  effected  in  this  direction  in  Diesel  propelled  vessels, 
although  in  certain  instances  steam  auxiliaries  have  been 
retained  and  a  small  boiler  installed  for  them,  but  this  is  an 
arrangement  which  is  not  likely  to  be  much  adopted.  Though 
it  is  impossible  to  give  a  figure  which  will  apply  generally, 
it  is  probable  that  in  the  majority  of  ships  the  weight  of  fuel 
if  propelled  by  Diesel  engines  is  approximately  one-fifth  of 
that  required  for  a  steamship,  and  hence  the  actual  monetary 
saving  in  fuel  costs  with  the  former  in  any  particular  case 
can  readily  be  estimated  with  a  reasonable  degree  of  accu- 
racy, if  the  market  prices  of  oil  and  coal  respectively  are 
obtained  at  the  ports  where  the  vessel  will  take  in  fuel. 
At  the  present  time  crude  oil  suitable  for  Diesel  engines  may 
be  obtained  at  most  Enghsh  ports  for  45s.  to  505.  per  ton, 
usually  the  former  figure,  and  even  better  terms  may  be 
made  by  contract  over  a  long  period.  From  this  it  may  be 
gauged  that  if  the  bunker  coal  exceeds  an  average  price  of 
10s.  or  lis.  per  ton  the  Diesel  engine  will  prove  more  econo- 
mical than  the  steam  engine  in  its  present  stage  of  efficient 
design  and  construction,  even    assuming  the    less  advan- 


DIESEL  ENGINES  FOR  MARINE  WORK         175 

tageous  ratio  of  fuel  in  the  two  cases,  namely,  Diesel  engine 
using  one-quarter  of  the  steam  engine. 

These  figures  assume  that  the  same  power  is  required 
whether  a  sliip  be  driven  by  Diesel  or  steam  engines,  and  this 
is  very  nearly  the  case,  the  balance  being  rather  in  favour 
of  the  former.  With  the  employment  of  the  Diesel  engine 
a  ship  can  be  built  with  rather  finer  lines  than  a  steamship, 
which  allows  a  certain  reduction  of  power  with  the  same  ves- 
sel speed.  On  the  other  hand  the  most  suitable  speed  of 
revolution  of  the  Diesel  engine  is  generally  speaking  rather 
above  the  most  economical  propeller  speed,  and  hence  a 
sUghtly  greater  power  is  needed,  but  these  two  matters 
balance  each  other,  at  any  rate  near  enough  for  all  practical 
purposes. 

The  saving  in  the  quantity  of  fuel  used  reflects  itself 
in  many  other  ways.  For  the  same  voj^age  since  onl};'  one- 
fifth  of  the  weight  of  fuel  is  required,  a  ver}^  valuable  bunker 
space  is  available  for  general  cargo  space,  and  this  is  more 
than  even  the  mere  relative  weights  signify,  since  oil  can  be 
stored  in  places  which  would  be  quite  unsuitable  for  coal, 
such  as  in  the  double  bottom  or  ballast  tanks. 

When  going  into  a  consideration  of  the  relative  running 
costs  of  a  Diesel  and  a  steam  installation,  the  cost  of  the  fuel 
is  not  by  any  means  the  sole  item  to  enter  into  the  calcula- 
tion. The  amount  of  lubricating  oil  necessary  is  perhaps 
greater  with  a  Diesel  motor,  but  on  the  other  hand,  no  fresh 
water  has  to  be  carried  for  boilers.  As  regards  the  cost  of 
upkeep  and  general  repairs,  there  is  no  reason  to  suppose 
that  the  motor  ship  should  be  at  a  disadvantage,  and  present 
experience  rather  points  to  the  fact  that  the  contrary  is 
the  case,  which  might  be  anticipated  for  the  reason  that 
there  is  much  less  machinery  and  fewer  parts  to  get  out  of 
order.  With  a  Diesel  ship  there  are  of  course  no  stokers 
required  and  the  number  of  attendants  is  much  reduced, 
this  applying  to  ships  of  all  sizes  and  engines  of  aU  powers. 
In  large  vessels,  however,  the  matter  is  a  more  vital  one  as 
so  many  firemen  have  to  be  employed,  far  exceeding  the 
engine-room  stafE  in  number,  as  may  be  instanced  in  the 


176  DIESEL  ENGINES  FOR  LAND  AND  MARINE  WORK 

extreme  case  of  the  Mauretania,  where  they  were  some  180 
firemen  as  against  35  engineers.  Coming  to  actual  facts 
it  may  be  as  well  to  state  that  in  a  small  vessel  of  2,000  tons 
displacement  with  a  Diesel  engine  of  500  B.H.P.  the  total 
3ngine-room  staff  consisted  of  four  men,  whilst  in  a  vessel 
propelled  by  a  Diesel  motor  of  1,500  B.H.P.  the  actual 
saving  effected  is  about  £300  per  annum,  due  to  the  reduced 
number  of  attendants  as  compared  with  a  steamship  of 
equal  power. 

The  saving  in  weight  of  fuel  consumed  per  unit  of  work 
in  a  Diesel  engine  may  be  utilized  at  sea  in  one  of  two  ways — 
the  range  may  be  increased  by  carrying  the  same  amount  of 
fuel  or,  with  the  same  range,  the  space  thus  economized 
may  be  employed  for  extra  cargo  carrying  capacity.     The 
first  method  is  of  enormous  value  for  war  vessels,  and  at  the 
lowest  estimate  the  radius  of  action  of  a  battleship  may  be 
increased  four-fold,  and  in  all  probability  allowing  for  the 
extra  economy  in  this  case  owing  to  the  average  power 
developed  being  so  much  below  the  maximum,  it  is  pro- 
bable that  something  like  seven  or  eight  times  the  radius 
might  be  reckoned  on  in  a  Diesel  engine  battleship  compared 
with  the  existing  type.     The  value  of  this  can  hardly  be 
too  strongly  emphasized,  particular!}'  in  the  case  of  countries 
whose    accessible    coaling    stations    are    infrequent.      For 
merchant  vessels  it  is  not  as  a  rule  of  great  moment  to 
increase  the  range,  though  it  may  frequently  be  advisable 
on  certain  services  owing  to  the  fact  that  fuel,  at  many  ports 
of  call  which  have  necessarily  to  be  used  as  coaling  stations, 
is  excessive  in  price,  and  the  lesser  consumption  of  fuel  there- 
fore allows  a  greater  choice  as  to  where  it  should  be  taken 
on  board,  leading  to  an  economy  impossible  with  steam- 
ships, owing  to  the  limitations  of  bunker  capacity.    However, 
most  frequently  the  shipowner  is  desirous  of  taking  full 
advantage  of  the  possibility  of  increasing  the  cargo-carrying 
capacity  of  his  ships  and  the  economy  of  fuel  consumption 
will  generally  be  put  to  this  purpose.     It  is  easy  to  see  how 
important   this   saving   may   become,   especially   for   ships 
making  long  voyages.     A  vessel  of  2,500  to  3,500  tons  dis- 


DIESEL  ENGINES  FOR  MARINE  WORK         177 

placement  propelled  by  a  steam  engine  of  about  1,100  or 
1,200  I.H.P.  would  consume  under  working  conditions  some 
15  tons  of  coal  per  day,  while  with  a  Diesel  engine  of  equal 
or  rather  greater  power  (say  1,000  B.H.P.)  would  require 
under  4  tons  of  oil,  showing  a  reduction  of  at  least  11  tons 
per  day,  or  if  the  vessel  bunkered  for  20  days,  a  total  saving 
of  220  tons.  Allowing  for  the  fact  that  oil  can  be  placed 
in  a  less  accessible  position  than  coal,  there  would  be  a  space 
available  for  carrying  cargo  to  the  extent  of  nearly  one- 
tenth  of  the  ship's  entire  displacement,  which  reflects  very 
considerably  on  the  earning  capacity  of  a  cargo  vessel. 

In  the  same  direction  lies  the  economy  in  the  space  occu- 
pied by,  and  the  weight  of  the  machinery  in  a  Diesel  ship 
compared  with  a  steamship.  On  this  point  again  the  ques- 
tion is  not  one  of  estimate  but  of  actual  fact.  The  average 
weight  of  machinery  in  vessels  propelled  by  reciprocating 
engines  of  modern  construction,  including  the  boilers  and 
accessories  is  in  the  neighbourhood  of  1  ton  for  every  6  to 
8  I.H.P.  developed  by  the  main  engines.  On  larger  vessels, 
particularly  those  propelled  by  steam  turbines,  the  weight 
is  somewhat  less  for  the  same  power,  and  particularly  is  this 
so  in  battleships,  while  in  destroyers  and  similar  vessels 
the  weight  of  the  machinery  may  be  reduced  to  15  I.H.P. 
per  ton.  This  reduction  however  is  usually  necessarily 
obtained  by  the  employment  of  high  speed  engines  of  speci- 
ally light  construction,  and  the  cases  are  therefore  not 
directly  comparable.  The  increase  in  speed  is  also  accom- 
panied by  a  diminution  in  propeller  efficiency,  which  of 
course  shows  itself  in  a  higher  coal  consumption  per  H.P. 
hour.  The  weight  of  a  marine  Diesel  engine  of  the  two-cycle 
single  acting  type  complete  with  all  auxiharies  and  accessories 
varies  between  10  and  15  B.H.P.  per  ton  of  total  weight, 
with  engines  of  the  slow  speed  type — that  is  to  say  under 
200  revolutions  per  minute.  For  high  speed  engines  which 
may  be  emploj^ed  in  certain  cases  as  much  as  25  B.H.P. 
may  be  developed  per  ton  of  machinery,  even  with  large 
powers,  and  already  single  engines  up  to  1,000  B.H.P.  have 
been  built  of  this  weight.     In  certain  instances,  therefore, 

N 


178  DIESEL  ENGINES  FOR  LAND  AND  MARINE  WORK 

where  the  question  of  obtaining  the  maximum  saving  in 
weight  becomes  a  vital  one,  there  is  some  hkeUhood  of  high 
speed  engines  being  adopted,  with  the  employment  of 
a  mechanical  or  other  gear  for  reducing  the  speed  to  give 
a  high  propeller  efficiency,  such  as  has  already  been  tried 
in  several  turbine-propelled  vessels.  It  is  obvious  that  this 
arrangement  will  only  be  considered  in  special  cases  since 
the  introduction  of  further  gear  is  always  to  be  deprecated 
at  sea,  and  the  higher  speed  engine  naturally  is  slightly  more 
costly  in  upkeep.  Considering  only  the  slow  speed  Diesel 
engine  of  the  ordinary  type  as  adapted  for  marine  work 
(e.g.  for  cargo  vessels),  it  has  been  found  that  the  approxi- 
mate saving  in  weight  for  a  1,500  shaft  H.P.  installation 
is  somewhere  in  the  neighbourhood  of  150  tons  in  favour 
of  the  Diesel  engine  as  compared  with  the  steam  equipment, 
and  approximately  the  same  ratio  applies  for  larger  powers. 
Together  with  the  saving  in  weight  there  is  also  a  consider- 
able reduction  in  the  space  occupied  by  the  machinery, 
since  a  Diesel  engine  requires  only  about  the  same  floor 
area  as  a  quadruple  expansion  steam  engine,  which  permits 
the  room  taken  by  the  boiler  to  be  thrown  open  for  other 
purposes  in  a  Diesel  ship. 

Allowing  for  all  the  economies  effected,  namely  in  weight 
of  fuel  carried,  weight  of  machinery,  and  in  engine-room 
space,  it  may  be  taken  as  a  safe  estimate,  that  with  almost 
any  class  of  vessel,  an  extra  cargo  can  be  carried  equivalent 
to  about  15  per  cent,  of  the  displacement  of  the  vessel.  This 
fact  makes  it  apparent  that  the  question  of  the  saving 
effected  in  the  fuel  bill,  important  though  it  is,  should  by 
no  means  be  the  determining  factor,  and  from  the  ship- 
owners' point  of  view,  the  increased  earning  capacity  must 
bo  seriously  considered. 

The  following  estimates  are  based  on  figures  given  by 
Herrn  Sauiberlich  in  a  paper  read  before  the  Schiffbautechni- 
schen  Gesellschaft,^  and  compare  the  saving  to  be  effected  in 
all  directions  by  the  employment  of  Diesel  engines  instead 
of  steam  engines.  It  is  of  course  difficult  to  give  any  exact 
*  Jahrhuch  der  Schiffbautechnischen  Gesellschaft,  Berlin,  1911. 


DIESEL  ENGINES  FOR  MARINE  WORK 


179 


comparisons  which  will  apply  general^,  since  the  varying 
services  and  conditions  under  which  different  vessels  run, 
will  determine  the  manner  in  which  the  shipowner  will  take 
advantage  of  the  economy  and  convenience  to  be  derived 
by  the  use  of  the  oil  engine,  w^hether  for  instance  the  bunker 
capacity  will  remain  the  same,  allowing  a  greater  radius,  or 
whether  the  range  of  the  vessel  mil  be  only  just  maintained 
and  the  full  economy  in  weight  of  fuel  carried  will  be  utilized 
to  its  utmost.  The  estimates  are  based  on  a  voyage  20 
days  out,  and  20  days  home,  with  four  round  trips  in  the 
year  or  160  days  steaming  per  annum.  The  oil  fuel  carried 
is  reckoned  as  sufficient  for  the  double  voyage,  while  the 
coal  in  the  case  of  the  steamships  is  sufficient  for  the  outward 
journey  only. 

The  cost  of  coal  is  taken  at  15-7  marks,  or  say  15s.  Qd.  per 
ton,  and  of  fuel  at  35  marks,  or  say  355.  per  ton  f.o.b.,  the 
fuel  consumption  for  the  Diesel  engine  being  0*49  lb.  per 
B.H.P.  hour,  and  the  coal  consumption  with  the  steam 
engine  at  about  1«25  lb.  per  I.H.P.  hour,  which  rather  favours 
the  steamship. 

Type  of  vessel 

Length feet 

Beam ,, 

Depth ,, 

Draught , 

Shaft  horse  power .      .      .      .B.H.P. 
Gross  tonnage      ....      tons 

Weight  of  fuel  carried  (double   voy- 
age in  case  of  Diesel  ship)  .      tons 

Extra  freight -carrying  capacity  with 
Diesel  ship tons 

Speed knots 

Fuel  consumption  ( -49  lb.  per  B.H.P. 
for  Diesel  and  1-25  lb.  per  I.H.P. 
steam  engine)        .      .   tons  per  day 

Fuel  cost per  day 

Daily  saving  in  fuel  cost  with  Diesel 
ship 

Wages  and  maintenance    of  engine- 
room  staff       .      .      .      .per  month 

Saving    in     engine-room    staff    M"itli 
Diesel  ship  .      .      .permontli 


Diesel  ship 

Steamship 

338 

338 

48 

48 

31-5 

31-5 

21-5 

21-5 

1,350 

1,500 

5,550 

5,400 

350 

480 

280 



10 

10 

7-1 

19-8 

£12  2s.  Od. 

£15  lis.  Od. 

£3  9s.  Od. 

— 

£52  6s.  Od. 

£72  lOs.  Od. 

£20  4a.  Od. 

__ 

180  DIESEL  ENGINES  FOR  LAND  AND  MARINE  WORK 

The  engine-room  staff  is  reckoned  as  three  engineers,  an 
assistant,  and  six  stokers  in  the  case  of  the  steam  vessel, 
and  three  engineers,  one  fitter,  and  two  greasers  with  the 
Diesel  ship,  or  practically  a  reduction  of  four  men  in  the 
latter  case.  The  saving  in  a  year's  worldng  may  be  sum- 
marized as  under,  taking  as  previously  mentioned  160 
steaming  days. 

£  s.  d. 
Increased  freight  of  280  tons  foiu'  round  trips  at  85.  per 

ton  for  single  voyage 896  0  0 

Saving  in  fuel  cost  at  £3  9s.  per  day  for  160  days  .      .      552  0  0 

Wages  and  maintenance  of  engine-room  staff      .      .      .      242  0  0 

Total £1,690     0     0 

Extra  interest  and  depreciation  due  to  higher  cost  of 

Diesel  plant 125     0     0 

Nett  saving  per  annvim  with  Diesel  ship  ....       £1,565     0     0 


These  figures,  inexact  as  they  must  necessarily  be,  are 
sufficient  to  show  what  a  great  economy  can  be  effected  on 
a  ■vessel  of  this  type  and  emphasize  the  point  that  the 
economy  in  fuel  is  by  no  means  the  chief  item  affecting 
comparisons  between  Diesel  and  steam  ships.  Were  the 
whole  of  this  advantage  swept  away  and  the  cost  of  the  fuel 
considered  the  same  in  both  cases  due  to  low  price  of  coal 
or  high  price  of  oil,  there  would  still  be  an  economy  of  over 
£1,000  per  annum  which  would  be  largely  increased  by 
adding  to  the  cargo-carrying  capacity  and  allowing  the  same 
weight  of  fuel  to  be  carried  in  the  two  ships. 

As  will  have  been  understood  from  previous  explanations 
the  oil  used  in  Diesel  engines  is  usually  of  the  heavy  bodied 
type  with  a  high  flash  point,  commonly  between  150°  F. 
and  300°  F.  The  possibility  of  fire  from  explosion  therefore 
need  not  enter,  and  this  is  of  importance  as,  apart  from  the 
absence  of  danger  to  the  engine-room  staff,  the  question  of 
higher  insurance  which  might  be  raised  were  oils  of  a  lower 
flash  point  necessary,  does  not  arise,  and  it  has,  in  fact,  been 
decided  by  the  insurance  companies  that  premiums  need 


DIESEL  ENGINES  FOR  MARINE  WORK         181 

be  no  higher  with  Diesel  boats  than  for  the  most  modern 
steamships. 

The  ease  and  cleanliness  with  which  oil  fuel  may  be  taken 
on  board  as  compared  with  the  operation  of  coaHng  is  a 
good  point  well  worlhy  of  consideration,  since  it  is  solely  a 
matter  of  pumping  from  a  reservoir  through  one  or  more 
pipes,  and  this  may  be  carried  out  with  great  rapidity.  The 
engine-room  arrangement  in  a  Diesel  ship  is  comparatively 
simjDie,  the  absence  of  the  complicated  steam  piping  being 
particularly  noticeable,  and  as  the  engine  is  entirely  self- 
contained  its  operation  is  wholly  controlled  by  the  engine- 
room  attendants,  which  is  a  point  to  be  noted  in  comparison 
with  the  dependence  of  the  running  of  a  steam  engine  on  the 
pressure  of  the  steam  from  the  boilers.  Up  to  the  present 
time  many  of  the  Diesel  ships  have  been  provided  with 
funnels  of  the  same  type  as  steamships,  to  get  rid  of  the 
exhaust  gases,  but  this  is  not  essential,  as  they  could  be  dis- 
charged from  the  side  of  the  vessel  if  required.  With  the 
general  adoption  of  Diesel  motors  for  war  vessels  funnels 
would  no  doubt  be  dispensed  with,  which  would  have  an 
important  bearing  on  the  effective  use  of  the  guns,  while 
the  absence  of  any  smoke  is  a  matter  of  some  importance  in 
preventing  the  possibility  of  locating  a  ship's  position  by 
this  means,  since  the  exhaust  gases  are  practical!}^  smokeless. 

With  regard  to  the  cost  of  the  machinery  for  a  Diesel 
motor  vessel,  the  Diesel  engines  at  the  present  time  are  at  a 
disadvantage.  As  a  rough  figure  over  a  wide  range  of  powers 
it  may  be  taken  that  the  Diesel  plant  is  from  10  to  20  per 
cent,  more  expensive  than  a  steam  installation,  including 
all  auxiliaries  in  both  cases.  The  cost  of  Diesel  engines  has, 
however,  been  falling  within  the  last  year  or  two  and  no 
doubt  will  soon  be  comparable  with  that  of  steam  plants  of 
the  same  power,  but  it  is  to  be  empliasized  that,  more  than 
with  any  other  machiner}',  price  cutting  is  to  be  strongly  de- 
precated in  view  of  the  j^erfection  of  construction  required 
with  Diesel  engines,  and  if  the  reduction  in  cost  price  be 
carried  too  far  it  will  inevitably  react  on  the  possibilities  of 
success  of  the  engine. 


182  DIESEL  ENGINES  FOR  LAND  AND  MARINE  WORK 

It  is  to  be  anticipated  that  the  cost  will  soon  be  in  the 
neighbourhood  of  £7  per  B.H.P.  for  single-acting  engines 
and  £5  per  B.H.P.  for  large  double-acting  motors,  and  there 
seems  no  reason  to  doubt  that  when  more  experience  is 
gained  the  price  of  Diesel  engines  of  very  large  size  will  not 
be  in  excess  of  that  of  steam  engines,  exclusive  of  boilers. 

Design  and  Arrangement  of  Diesel  Marine  Engines. 
— There  are  several  important  points  to  be  observed  in  the 
design  and  arrangement  of  ship's  machinery — all  so  essen- 
tial as  to  render  it  difficult  to  define  any  one  of  them  as  the 
chief.     Briefly,  they  may  be  classed  as  follows  : — 

(1)  The  engines  must  be  reliable,  of  simple  construction 
and  easy  of  operation. 

(2)  The  engines  must  be  capable  of  rapid  and  frequent 
reversal  by  a  simple  means. 

(The  question  of  frequent  reversal,  as  in  manoeuvring, 
has  an  important  bearing  on  the  design  of  a  Diesel  ship 
where  the  engine  is  reversed  by  compressed  air,  inasmuch  as 
the  air  reservoirs  must  be  of  ample  capacity  for  all  demands.) 

(3)  The  engines  should  have  a  wide  variation  of  speed 
both  ahead  and  astern,  which  variation  must  be  easily 
accomplished  preferably  by  one  handle  or  lever. 

(4)  The  fuel  consumption  should  be  low,  not  only  at 
maximum  engine  power,  but  within  a  wide  variation. 

(5)  The  weight  and  space  occupied  by  the  machinery 
should  be  as  low  as  possible,  but  should  not  be  sacrificed  to 
high  and  generally  inefficient  propeller  speed. 

The  question  of  the  employment  of  two  or  four  cycle 
Diesel  engine  for  marine  purposes  has  been  discussed  in 
Chapter  II  and  need  not  be  further  entered  into.  One  of 
the  chief  problems  which  confronts  the  designer  is  the 
number  of  cylinders  of  the  engine  for  a  given  power,  which 
will  provide  sufficient  evenness  of  operation,  and  it  is  to  be 
remembered  that  flywheels  are  to  be  avoided  if  possible, 
and  in  any  case  must  be  small  in  order  to  allow  rapid  man- 
ceuvi'ing  of  the  vessel.  As  in  most  other  questions  regarding 
marine  engines  there  are  two  antagonistic  conditions  to  be 
satisfied  as  far  as  circumstances  permit,  namely,  that  the 


s 


.fTt-- 


)00  H.P.   ^^ 


Fig.    84.— Engine  Room  Arrangement  of  Motor  Ship  equipped  with  a  2,000  H.P.  Two-Cycle  Engii 


DIESEL  ENGINES  FOR  MARINE  WORK        183 

engine  should  run  smoothly,  and  that  simplicity  is  essential 
and  the  number  of  working  parts  small.  For  the  first,  the 
higher  the  number  of  cylinders  the  better,  while  the  second 
condition  is  best  complied  with  when  there  is  a  minimum 
number  of  cylinders.  In  no  case  is  it  hkely  that  an  engine 
of  less  than  three  cyhnders  will  be  employed  for  marine 
work,  and  this  only,  of  course,  with  the  two-cycle  type. 
In  actual  practice  with  a  two-cycle  single  acting  engine 
there  are  usually  four  or  six  cylinders,  though  there  may 
possibly  be  more,  particularly  for  the  larger  powers,  and 
with  six  cylinders  only  a  small  flywheel  is  necessary  ;  these 
two  types  are  the  standards  adopted  by  some  manufacturers 
— notably  Messrs.  Sulzer  Brothers.  With  four-cycle  en- 
gines, the  least  number  of  cylinders  which  is  advisable  is 
six,  in  order  to  give  an  even  turning  moment.  Very  fre- 
quently, however,  more  are  employed,  particularly  with 
engines  for  submarines  where  so  many  other  factors  enter 
into  consideration,  and  eight  is  a  common  number. 

If  three  cylinders  be  employed  for  a  double  acting  engine, 
no  flywheel  is  required,  but  the  question  of  balancing  the 
engine  and  rendering  it  free  from  vibration  is  compUcated 
by  the  introduction  of  the  scavenge  pumps.  However,  three 
cylinders  are  being  adopted  in  most  cases  with  engines  of  this 
type.  For  very  large  engines  the  question  does  not  resolve 
itself  merely  into  the  advisable  number  of  cj^linders  from 
the  point  of  view  of  even  turning  moment  and  absence  of 
vibration,  but  is  dependent  on  the  power  which  can  be 
developed  in  an  engine  with  a  reasonable  number  of  cyhnders 
— in  other  words,  on  the  maximum  horse  power  which  can  be 
obtained  from  one  cyhnder.  In  any  case,  with  very  large 
engines,  for  several  reasons,  chief  among  which  is  the  neces- 
sity for  simpHcity,  it  will  probably  be  inadvisable  to  have 
more  than  eight  cylinders,  and  hence  the  need  will  arise  for 
twin  or  triple  screw  Diesel  ships,  which  have  much  to  com- 
mend them  as  allowing  greater  efficiency  and  giving  better 
manoBuvi'ing  facilities.  Even  for  lower  powers,  tmn  screw 
Diesel  vessels  will  probably  become  common,  at  any  rate 
for  some  time  ahead,  until  greater  experience  has  been  gained 


184  DIESEL  ENGINES  FOR  LAND  AND  MARINE  WORK 

with  very  large  engines,  and  this  is  instanced  in  the  many 
twin  screw  boats  now  in  service  and  under  construction, 
some  with  engines  of  as  much  as  5,000  H.P.  The  largest 
number  of  cylinders  which  has  yet  been  used  in  a  Diesel 
engine  is  eight,  and  no  doubt  this  will  remain  the  limit. 

It  will  be  seen  that  a  Diesel  marine  engine  in  general  has 
more  cylinders  than  a  steam  engine  of  the  same  power,  which 
is  in  itself  a  disadvantage  from  the  point  of  view  of  adding 
to  the  complication  of  the  machinery.  On  the  other  hand, 
in  the  event  of  a  breakdown  of  one  or  more  cylinders,  all 
the  others  can  operate  quite  satisfactorily,  so  that  the  possi- 
bilities of  total  disablement  are  small  in  the  extreme,  while 
at  any  time  a  number  of  the  cylinders  can  be  shut  down, 
giving  a  more  economical  operation  of  the  engine  at  low 
powers.  The  multiplicity  of  cylinders  has  always  been 
taken  advantage  of  in  some  designs  mentioned  later  in  aiding 
the  manoeuvring  of  the  vessel. 

For  the  majority  of  ships  of  between  3,000  to  5,000  tons, 
of  which  the  greater  portion  of  the  world's  shipping  is  com- 
posed, the  most  economical  propeller  speed  consistent  with 
high  propeller  efficiency  is  generally  not  more  thaji  100  re- 
volutions per  minute,  and  as  Diesel  engines  must  adapt  them- 
selves to  existing  conditions  (i.e.  to  present  limitations  of  pro- 
peller efficiency)  the  greater  number  of  Diesel  marine  engines 
have  to  be  designed  to  run  at  about  this  speed  or  very  little 
higher  unless  gearing  be  introduced.  For  battleships,  sub- 
marines, and  fast  vessels  generally  a  considerably  higher  pro- 
peller speed  is  allowable,but  these  are  special  cases  which  have 
to  be  considered  separately.  Stationary  Diesel  engines  of  the 
slow  speed  type  thus  run  at  a  higher  rate  of  revolution  than 
the  marine  engine,  the  weight  of  which  is  therefore  some- 
what in  excess  of  the  land  engine,  and  the  space  occupied  is 
rather  greater.  No  trouble  is  however  experienced  in  the 
design  of  the  slower  engine,  and  were  there  any  essential 
difficidty  in  the  construction,  or  difference  in  the  economy, 
it  would  of  course  be  advisable  to  sacrifice  something  in  the 
propeller  efficiency  and  run  this  engine  at  a  higher  speed, 
but  such  is  however  not  the  case. 


DIESEL  ENGINES  FOR  MARINE  WORK         185 

Of  parlicular  importance  with  marine  engines  is  the  ques- 
tion of  rapid  variation  of  speed  between  a  wide  range, 
namely  between  the  speeds  corresponding  to  full  vessel 
speed  and  dead  slow.  An  oil  engine  of  the  Diesel  type  lends 
itself  readily  to  such  operation  since  it  is  only  a  matter  of 
regulating  the  quantity  of  fuel  admitted  to  the  cyUnders, 
which  is  carried  out  with  the  utmost  ease  by  hand.  In  slow 
speed  engines  running  normally  at  about  100  to  130  revolu- 
tions per  minute,  40  revolutions  per  minute  can  be  obtained, 
which  is  as  low  as  required,  while  with  higher  speed  engines 
the  minimum  speed  is  not  much  above  this  ;  for  instance,  a 
1,000  B.H.P.  marine  engine  of  the  two-stroke  cycle  type 
with  a  top  speed  of  about  130  revolutions  per  minute  can  be 
brought  down  by  hand  regulation  to  30  revolutions  per 
minute,  though  such  a  wide  variation  is  not  always  attain- 
able without  sj^ecial  arrangements.  A  novel  method  to 
obtain  a  greater  reduction  of  speed  than  is  easily  possible 
with  the  ordinary  design  of  Diesel  marine  engine,  and  to 
give  very  rapid  and  convenient  manoeuvring,  is  that  of 
Messrs.  Cockerill,  AAho  constructed  an  engine  of  six  cylin- 
ders in  two  sets  of  three,  with  a  coupling  in  the  middle  which 
is  capable  of  disconnecting  one  set  from  the  other.  The 
engine  remote  from  the  propeller  shaft  has  coupled  to  it  an 
air  compressor  ;  in  the  ordinary  running,  the  two  halves  of 
the  engine  are  coupled  together  and  the  machine  runs  as  an 
ordinary  six-cylinder  four-cj^cle  motor,  and  the  speed  can  be 
varied  to  a  large  extent  in  the  ordinary  way.  For  very  low 
speeds  the  two  halves  are  disconnected,  and  the  one  half 
drives  the  air  compressor  which  supplies  compressed  air 
directly  to  the  other  half  of  the  engine,  which  then  runs  as 
an  air  motor,  and  the  speed  can,  of  course,  be  reduced  to  suit 
any  requirements.  When  manoeuvring  the  same  arrange- 
ment is  adopted  and  also  in  reversing.  This  type,  however, 
is  not  likely  to  receive  wide  adoption,  and  was  mainly 
experimental. 

The  Diesel  engine  of  the  land  type  has  been  developed, 
as  far  as  general  design  and  construction  are  concerned,  some- 
what on  the  lines  of  the  gas  engine,  and  hence  the  trunk 


186  DIESEL  ENGINES  FOR  LAND  AND  MARINE  WORK 

position  has  been  wellnigh  universally  adopted,  although  the 
separate  crosshead  design  was  tried  by  some  makers  and 
abandoned,  as  it  necessitated  shorter  pistons  and  gave  less 
bearing  surface.  With  marine  engines,  however,  the  ques- 
tion of  the  employment  of  the  separate  crosshead  becomes 
more  debatable,  chiefly  owing  to  the  importance  justly 
attached  by  marine  engineers  to  accessibility  and  ease  in 
dismanthng.  For  double  acting  engines  crossheads  are  of 
course  essential,  but  opinion  is  divided  regarding  the  matter 
for  single  acting  engines,  both  two  and  four  cycle.  The 
main  advantage  of  the  trunk  piston  is  that  the  height  of 
the  engine  is  less  than  with  a  crosshead  engine,  while  the  cost 
is  also  somewhat  reduced.  Possibly  with  the  ultimate 
design  of  Diesel  marine  engine  the  trunk  piston  will  be 
adopted  for  relatively  small  and  high  speed  engines, 
but  in  the  early  days  it  is  advisable  to  conform  with  the 
practice  to  which  marine  engineers  have  so  long  been  accus- 
tomed and  retain  the  crosshead,  which  no  doubt  gives  more 
certainty  of  reUability.  Admittedly  very  little  trouble 
has  been  occasioned  on  land  with  the  long  pistons,  but 
marine  practice  is  on  a  different  footing,  and  excess  of  caution 
is  not  to  be  deprecated.  There  is  of  course  always  a  shght 
chance  of  the  piston  seizing,  with,  a  trunk  piston,  and  though 
this  need  not  be  enlarged  upon,  the  pomt  should  not  be  lost 
sight  of. 

For  Diesel  marine  engines  of  large  power,  and  particularly 
those  of  the  two  cycle  and  double  acting  type,  coohng  of  the 
pistons,  valves  and  bearings  has  to  be  resorted  to.  This 
is  not  a  matter  of  any  serious  difficulty,  although  there  is 
divergence  of  opinion  as  to  the  most  effective  means  to 
employ.  In  four-cycle  engines  of  comparatively  small  size 
it  has  been  found  sufficient  to  cool  the  pistons  by  allowing 
the  air  dra\\Ti  into  the  cyhnder  during  the  suction  stroke  to 
pass  through  the  piston,  thus  serving  a  dual  purpose  of  warm- 
ing the  air  and  coohng  the  piston.  The  more  general  method 
is  to  effect  a  circulation  of  water  or  oil  through  a  cooling 
tank.  There  is  no  doubt  of  the  advantage  of  coohng  pistons 
and  rods  by  oil,  as  with  water  not  only  may  leakages  detri- 


DIESEL  ENGINES  FOR  IMARINE  WORK         187 

mentalh'  affect  the  lubrication,  but  it  is  ako  always  liable  to 
become  mixed  with  the  oil  indirectly,  and  even  get  into  the 
main  bearings.  For  this  reason  some  manufacturers  have 
adopted  oil  coohng  in  preference  to  water  cooling,  though 
many  are  maldng  attempts  to  run  large  engines  without  any 
special  coohng,  and  this  would  of  course  be  by  far  the  best 
solution.  As  regards  piston  cooling  the  Diesel  engine  is  more 
favourably  placed  than  the  explosion  type  of  internal  com- 
bustion, since  there  is  more  time  for  the  heat  to  be  carried 
away  bj^  the  jacket  water,  and  the  temperature  of  the  piston 
does  not  rise  to  the  same  extent.  The  exhaust  valves  in 
marine  engines,  which  are  the  chief  ones  liable  to  trouble 
through  overheating,  can  very  conveniently  be  cooled  by  the 
same  water  as  is  used  for  the  cyhnder  jackets.  The  water 
enters  the  body  of  the  valve  casing  which  serves  as  a  guide 
for  the  valve  rod,  and  passes  into  the  valve  seat,  which  is  of 
a  box  form,  and  thence  up  through  the  hollow  valve  rod  and 
out  through  the  top.  With  regard  to  the  coohng  of  bear- 
ings, if  forced  lubrication  is  employed,  as  is  the  case  with,  some 
types  of  Diesel  marine  engine,  the  oil  is  passed  through  an 
oil  cooler  usually  arranged  in  the  bed-plate,  but  with  the 
ordinary  method  of  lubrication  the  bearings  are  water  cooled 
by  branches  off  the  main  cylinder  coohng  water  supply 
pipes. 

Great  attention  has  to  be  paid  to  the  arrangements  for 
the  supply  of  scavenge  air  in  a  two-cycle  engine,  and  the 
point  is  of  even  greater  importance  with  motors  of  the  two- 
cycle  double  acting  type.  Since  the  scavenge  pumps  are 
such  a  vital  detail  of  the  engine  they  are  now  very  frequently 
made  in  duplicate  for  marine  work  \vith  the  single  acting 
tw^o-C3'cle  engine,  while  in  double  acting  engines  it  is  advisable 
to  have  one  scavenge  pump  for  each  working  cyhnder,  and 
this  arrangement  is  hkely  to  be  frequently  adopted .  When 
two  scavenge  pumps  are  emploj^ed  for  the  single  acting 
engine,  each  is  made  of  about  60  per  cent,  of  the  full  engine 
capacity  or  rather  more,  so  that  in  the  event  of  breakdown 
of  one  pump,  the  disablement  would  not  be  very  serious. 
The  engine,  too,  is  sometimes  di\^ded  into  two  sections,  that 


188    DIESEL  ENGINES  FOR  LAND  AND  MARINE  WORK 


90   &0   10   fjO  60  'lO  30   20  to 

0                        METRES                           J 

T     1      1      1      1     1      1      1      illii 

Fig.  85. — Details  of  one  of  the  two  Scavenge  Pumps  for   1,500  B.H.P. 
CareLs'  Type  Marine  Diesel  Engine. 


is  to  say,  a  6-cylmcler  engine  is  treated  as  two  3-cylinder 
engines,  and  a  4-cylinder  as  two  2-cylinder  engines,  and  one 
scavenge  pump  ordinarily  supplies  each  half  of  the  engine. 
The  scavenge  pumps  vrvih.  double  acting  engmes  are  arranged 
on  the  crank  shafting  in  line  ^ith  the  working  cyhnders, 


DIE8EL   ENGINES   FOR  MARINE   WORK         189 

preferably  half  at  each  end,  when  a  good  balancing  effect 
may  be  obtamed  by  a  proper  disposition  of  the  crank  angles, 
though  there  are  other  methods  adopted,  described  later. 
With  single  acting  engines  the  scavenge  pumps  may  either 
be  on  the  end  of  the  crank  shaft  or  arranged  in  front  of  the 
engine  and  driven  by  levers,  which  has  the  advantage  of 
allowing  the  crank  shaft  to  be  in  two  interchangeable  halves, 
which  would  not  otherwise  be  possible,  and  also  makes  the 
resemblance  of  the  engine  to  a  steam  engine  more  marked, 
which  though  apparently  a  small  matter  is  well  worthy  of 
consideration.  It  must  be  stated  that  although  at  least  two 
scavenge  pumps  are  advisable  for  two-stroke  engines  they 
are  not  essential,  and  in  some  cases  of  1,000  B.H.P.  single 
acting  marine  engines  only  one  pump  is  employed  driven  off 
the  end  of  the  crank  shaft  and  in  a  line  with  the  working 
cylinders. 

In  the  design  of  scavenge  pumps  the  first  point  of  import- 
ance is  the  provision  of  an  ample  supply  of  air,  but  it  is  diffi- 
cult to  say  what  should  be  the  exact  capacity  of  the  pumps 
relative  to  the  working  cylinder  volume.  That  it  must  be 
in  excess  of  the  latter  is  agreed  ;  and  for  ordinary  marine 
engines  and  also  low  speed  land  engines  of  the  two-cycle 
type,  the  volume  of  the  scavenge  pump  is  frequently  made 
about  25  per  cent,  greater  than  the  working  cylinder,  but 
in  high  speed  engines  the  difference  may  be  as  much  as  50 
per  cent.  The  scavenging  air  does  not  enter  the  cylinders 
direct,  but  passes  through  a  receiver,  usually  of  small  dimen- 
sions, which  is  desirable  from  the  point  of  view  of  allowing 
the  pressure  to  be  rapidly  raised  and  kept  constant — a 
particularly  important  matter  for  marine  engines  when 
reversing.  In  most  of  the  two-cycle  engines  which  have 
hitherto  been  built  for  marine  work  the  admission  of  scavenge 
air  is  carried  out  through  valves  actuated  by  levers  in  turn 
operated  by  cams  on  the  cam  shaft,  just  as  the  exhaust  valves 
in  the  four-cycle  engine.  The  arrangement  adopted  by 
some  firms  is  shown  in  Fig.  86,  two  scavenge  valves  being 
employed  for  each  cylinder,  one  on  each  side  of  the  fuel  inlet 
valve.     In  the  first  position  in  Fig.  86  the  piston  is  at  the 


190    DIESEL  ENGINES  FOR  LAND  AND  MARINE  WORK 

top  dead  centre  and  the  fuel  valve  is  open  to  admit  the  oil, 
in  the  third  position  the  exhaust  ports  are  fully  uncovered, 
the  exhaust  gas  being  expelled  by  the  incoming  air. 


For  larger  engines,  valves  are  inconvenient  for  the  admis- 
sion of  the  scavenge  air,  owing  to  the  size  necessitated  to 
aUow  the  requisite  amount  of  air.     For  this  reason  ports 


DIESEL   ENGINES   FOR    MARINE   WORK 


191 


instead  of  valves  have  recently  been  introduced,  and 
with  this  arrangement  there  are  two  sets  of  ports  at  the 
bottom  of  the  cylinder,  one  on  each  side  for  the  exhaust  and 
for  the  scavenge  air.  This 
method  may  be  generally 
employed  for  all  marine 
engines  of  the  two-cycle 
type  in  the  future,  possess- 
ing as  it  does  the  advan- 
tage of  simplicity,  con- 
venience and  rehability, 
though  there  seems  to  be 
some  doubt  as  to  whether 
it  gives  so  efficient  a 
scavenging  effect.  There 
are  then  but  two  (and 
in  some  cases  only  one) 
valves  for  each  cylinder — 
the  fuel  inlet  valve  and 
the  starting  valve — and 
this  practically  reduces 
the  operation  of  revers- 
ing to  an  alternation  of 
the  position  of  two  cams, 
or  possibly  one. 

Fig.  87  shows  diagram- 
matically  the  arrangement 
of  ports  adopted  with 
this  system  by  the  A,  B. 
Diesels  Motorer  of  Stock- 
holm, A  being  the  exhaust 
ports,  B  the  scavenging 
air  pipe.     The  design  of  ^-^    87.— Two-Cycie    Engine,    with 

the    piston    head    is    such        Scavenge  Ports  instead  of  Valves. 

that    the    exhaust    ports 

are  opened  on  the  doMn  stroke  some  little  time  before 
the  scavenging  ports,  so  that  part  of  the  burnt  gases  may 
be  rejected  and  the  pressure  much  reduced  before  the  air  is 


.  .._ 


192    DIESEL  ENGINES  FOR  LAND  AND  MARINE  WORK 

admitted,  while  on  the  up  stroke  the  scavenge  ports,  of 
course,  are  closed  before  the  exhaust  ports. 

As  is  seen  from  the  diagram  which  represents  relatively  the 
approximate  length  of  the  ports,  the  duration  of  the  period 
for  the  admission  of  scavenging  air  is  small  and  hence  the 
velocity  must  be  high.  This  seems  to  point  to  relatively 
large  pressure  of  scavenging  air,  to  give  the  requisite  volume, 
but  this  involves  more  work  for  the  pumps,  while  a  low  pres- 
sure necessitates  heavier  and  larger  cylinders,  pipes  and 
valves.  A  compromise  has  therefore  to  be  struck,  and  as 
previously  mentioned,  the  actual  pressure  is  usually  between 
3  and  6  lb.  per  sq.  inch,  dependent  on  the  speed  of  the 
engine. 

The  whole  of  the  Isngth  of  the  cylinder  occupied  by  the 
various  ports  is  practically  wasted  from  the  point  of  view  of 
power  production,  and  the  cylinder  volume  is  therefore 
relatively  larger  than  with  a  four-cycle  engine,  which  is  one 
of  the  chief  reasons  why  it  is  impossible  to  get  twice  the  power 
from  a  two-cycle  motor  compared  with  a  four-cycle  engine  of 
the  same  size.  Roughly,  some  25  per  cent,  of  the  cylinder 
volume  in  a  two-cycle  ported  engine  is  not  available  for 
useful  work  of  power  production,  while  for  the  same  reason 
a  long  piston  has  to  be  adopted,  though  this  is  minimized  by 
the  employment  of  a  crosshead  and  connecting  rod. 

A  good  deal  of  attention  has  been  paid  lately  to  the 
question  of  scavenging  by  means  of  ports  instead  of  valves, 
and  some  methods  adopted  are  described  later  when  giving 
a  detailed  description  of  the  particular  types  of  marine 
engines.  The  main  objection  which  had  been  urged  against 
the  employment  of  ports  was  that  the  scavenging  effect  was 
not  so  good  as  with  valves,  and  that  consequently  incom- 
plete combustion  was  obtained,  giving  a  smoky  exhaust 
and  higher  fuel  consumption  in  an  engine  with  scavenge 
ports.  Careful  investigation,  however,  which  has  lately 
been  carried  out,  tends  to  show  that  provided  special 
arrangements  are  adopted,  there  is  no  reason  why  the 
efficiency  should  not  be  equally  high  and  the  combustion 
practically  perfect,     In  a  long  series  of  experiments  it  has 


DIESEL   ENGINES  FOR  MARINE  WORK         193 

been  found  that  the  results  obtained  with  ports  are  within 
I  per  cent,  of  those  with  valves. 

As  has  been  stated,  the  supply  of  scavenge  air  required 
in  a  two-cycle  single-acting  engine  may  be  up  to  1-5  times 
the  vohune  of  the  cylinder,  or  even  more,  depending  on  the 
pressure  employed.  The  inlet  areas,  if  valves  be  used, 
must  therefore  be  very  large  in  the  case  of  high  powered 
engines,  and,  for  instance,  an  1,800  H.P.  motor  (and  even 
smaller  engines)  has  four  scavenge  valves.  This  is  the 
largest  marine  engine  which  has  been  built  on  such  a  prin- 
ciple, and  the  point  arises  as  to  whether  the  use  of  valves 
would  not  cause  a  limitation  in  the  maximum  output  of 
a  two-cycle  motor.  Even  allowing  that  it  would  still  be 
possible  to  use  four  valves  in  engines  with  still  larger 
cylinders,  the  complication,  cost,  weight,  and  possible 
unreliability  are  all  augmented — features  which  are  much 
to  be  deprecated. 

It  need  only  be  pointed  out  that  in  a  six-cyHnder  engine 
of  large  size,  twenty-four  scavenge  valves  are  necessary 
with  a  corresponding  number  of  spares,  to  show  what  an 
advantage  is  gained  by  dispensing  with  them.  It  must 
be  remembered  that  in  scavenging  with  valves,  the  time 
of  opening  must  be  small  (to  allow  sufficient  compression) 
and  the  speed  of  scavenging  high,  which  is  not  productive 
of  the  best  effect.  With  ports  the  time  can  be  longer,  the 
part  areas  can  be  considerable,  and  if  desired  the  pressure 
of  the  air  can  be  reduced,  and  in  some  designs  it  is  as  low 
as  2^  lb.  per  sq.  in.  above  atmosphere. 

Methods  of  Reversing  Diesel  Engines. — The  problem 
of  reversibility  has  never  been  one  of  serious  importance 
with  Diesel  engines,  since  it  is  but  a  matter  of  detail  to 
render  an  engine  capable  of  running  in  either  direction. 
The  only  necessity  in  reversing  is  to  arrange  the  valve 
mechanism  so  that  the  valves  open  at  a  different  period 
relative  to  the  position  of  the  crank  or  piston,  and  this  in 
turn  is  dependent  solely  on  the  positions  of  the  cams  which 
operate  the  various  valves.  In  a  four-cycle  engine  the 
exhaust,  starting,  air  admission,  and  fuel  admission  valves 

o 


194  DIESEL  ENGINES  FOR  LAND  AND  MARINE  WORK 

all  have  to  open  at  a  different  time  when  the  engine  is  running 
in  the  reverse  direction.  In  a  two-cycle  motor  with  exhaust 
ports,  only  the  scavenging  valve,  fuel  inlet  valve  and  starting 
valve  are  affected,  while  if  scavenge  ports  be  adopted  the 
fuel  and  starting  valve  alone  have  to  be  operated.  In  some 
types  of  reversible  engines,  starting  is  effected  by  means  of 
the  scavenging  air  pump  in  which  there  is  but  a  single  valve 
and  cam  to  operate  in  reversing  the  engine,  and  the  advan- 
tage of  the  two-cycle  engine  over  the  four-cycle  in  the  matter 
of  reversing  is  apparent  since  simplicity  is  of  such  moment 
in  marine  work. 

In  mirine  engines,  the  ordinary  type  of  horizontal  cam 
shaft  has  to  be  adopted,  and  the  arrangement  of  cams  follows 
on  the  lines  of  that  for  stationary  work.  There  are  generally 
speaking  two  methods  adopted  for  reversing  Diesel  engines, 
which  process  comprises,  in  effect,  the  alteration  of  the  timing 
of  the  opening  of  the  valves.  There  must  obviously  be  two 
sets  of  cams,  that  is  two  cams  or  the  equivalent  for  each  cam 
lever  operating  a  valve,  and  the  methods  hitherto  employed 
have  consisted  either  in  having  two  sets  of  cams  on  the  same 
horizontal  shaft,  and  moving  the  shaft  longitudinally  when 
reversing,  or  else  there  aie  two  distinct  cam  shafts,  either  of 
which  may  be  moved  so  as  to  allow  its  cams  to  actuate  the 
cam  lever,  the  other  shaft  being  then  out  of  range  of  the 
levers.  There  are  of  course  various  modifications,  but 
speaking  generally  the  main  principles  described  are  not 
departed  from. 

Auxiliaries  for  Motor  Ships. — In  a  general  considera- 
tion of  the  question  of  the  adoption  of  a  new  type  of  engine 
for  marine  propulsion,  the  many  auxiliary  appliances  on 
ships  have  to  be  remembered,  their  importance  being  easily 
gauged  from  the  fact  that  they  usually  require  some  20  to  25 
per  cent,  of  the  power  of  the  main  engine  for  their  operation. 
For  many  years  past  there  has  been  a  tendency  to  replace 
steam-driven  auxiliaries  and  employ  electric  motors  for 
their  drive,  the  advantage  of  this  from  the  point  of  view 
of  economy  in  operation,  convenience,  absence  of  stand-by 
losses,   and   avoidance  of  trouble  through  freezing  being 


DIE.SEL   ENGINES   FOR   MARINE   WORK         195 

at  once  apparent.  The  adoption  of  electricity  for  driving 
all  ships'  auxiliaries  seems  therefore  to  be  the  ultimate 
solution  in  vessels  of  moderate  and  large  size,  and  this 
method  is  to  be  adopted  on  some  of  the  big  Diesel  engine 
vessels  now  being  constructed.  Diesel  engines  are  employed 
for  the  dynamo  drive,  and  the  relatively  great  economy  com- 
pared with  steam  engines  emphasizes  the  total  saving  in 
fuel  in  the  vessel,  and  this  is  particularly  the  case  in  compari- 
son with  vessels  whose  auxiliaries  are  steam  driven,  since 
the  wastefulness  of  such  machines  is  notorious. 

With  aU  Diesel  ships  it  is  quite  essential  that  a  second  air 
compressor  should  be  available  apart  from  the  one  driven 
direct  off  the  engine,  for  the  supply  of  high  pressure  air,  since 
so  much  is  used  when  manoeuvring,  and  a  breakdown  of  the 
pump  would  render  the  vessel  helpless  if  there  were  but  one. 

It  is  conceivable  that  the  main  engine  may  make  a  few 
revolutions,  stop  for  a  few  minutes  and  then  be  required  to 
reverse,  and  during  this  period  it  is  clear  that  the  compressor 
on  the  main  engine  cannot  itself  furnish  sufficient  air  for 
this  work.  Indeed,  it  might  be  necessary  to  manoeuvre  the 
whole  engine  v,ith.  air  when  going  quite  slowly,  and  for  this 
purjDose  an  auxiliary  compressor  of  large  capacity  must  be 
installed. 

Experience  will  determine  eventually  what  capacity  this 
auxiHary  machine  should  be,  but  the  practice  at  present  is 
to  make  it  from  half  to  three-quarters  the  capacity  of  the 
compressor  on  the  engine  itself. 

When  steam  is  provided  on  the  vessel  (see  later),  in  order 
to  work  the  cargo  ^^•inches,  steering  gear  and  other  auxiliary 
machinery,  the  auxiliary  compressor  is  usually  driven  by  a 
steam  engine. 

As  a  very  large  number  of  vessels  that  have  hitherto  been 
put  in  service  are  provided  with  steam-diiven  deck  and 
other  machinery,  it  is  not  surprising  that  this  arrangement 
should  have  been  adopted  to  a  large  extent.  Without 
going  into  the  question  of  advantages  and  disadvantages 
of  the  steam  drive  as  compared  with  electricity  or  indepen- 
dent oil  engine  operation  (this  point  is  discussed  elsewhere), 


196  DIESEL  ENGINES  FOR  LAND  AND  MARINE  WORK 

it  may  be  mentioned  that  even  on  some  ships  wliere  steam 
is  extensively  employed,  an  auxiliary  Diesel  driven  com- 


pressor is  installed  in  the  engine  room.     When  the  machine 
is,  however,  coupled  to  a  steam  engine,  its  design  naturally 


DTEREL   ENGINES   FOR  MARINE   WORK 


197 


does  not  dilTer  from  ordinary  practice,  and    both  the  ver- 
tical and  quadruplex  type  have  been  commonly  utilized  for 


the    purpose.     The    former    is,   however,   gaining    ground, 
particularly  for  use  in  conjunction  with  large  engines. 
In  addition  to  the  question  of  manauvring  it  is  desirable 


198    DIESEL  ENGINES  FOR  LAND  AND  MARINE  WORK 

to  have  a  compressor,  which  can  be  of  smaller  dimensions, 
which  is  capable  of  supphdng  air  for  filling  the  starting 
bottles,  in  case  the  whole  of  the  air  should  be  lost,  when  the 
vessel  is  at  anchor  for  some  time,  or  is  laid  by.  These 
smaller  machines  can  be  driven  by  a  small  steam  engine,  if 
the  vessel  has  steam  for  auxiliary  work,  by  an  electric  motor, 
or  by  a  small  oil  engine. 

For  very  large  Diesel  engines  such  as  \A'ill  be  required  in 
large  ships  in  the  near  future,  high  power  independent  com- 
pressors will  be  recpiired,  and  these  will  necessarily  be  driven 
by  separate  engines. 

It  is  obvious  that  a  very  suitable  arrangement  for  the 
operation  of  the  auxiliaries  in  small  vessels  could  be  by  com- 
pressed air,  while  driving  such  auxiliaries  as  can  be  accom- 
modated in  the  engine  room,  direct  off  the  reserve  engine 
coupled  to  the  compressor.  This  method  has  been  adopted 
in  some  cases,  the  dynamo  and  some  pumps  being  driven 
by  the  auxiliary  engine,  while  the  steering  gear  and  other 
auxiliaries  are  driven  by  compressed  air. 

In  view  of  the  fact  that  so  much  experience  has  been 
obtained  with  steam-driven  auxiliaries,  particularly  -wdnches, 
windlasses  and  steering  gear,  it  has  been  proposed  that  even 
in  Diesel  engine  boats,  such  method  of  operation  be  still 
employed.  This  suggestion  has,  in  fact,  been  generally 
adopted,  and  is  likely  to  continue  to  find  acceptance  among 
some  shipowners  and  engineers.  The  arrangement  necessi- 
tates the  installation  of  a  donkey  boiler  to  supply  the  steam, 
and  this  may  be  conveniently  oil  fired,  though  it  has  been 
proposed  to  utilize  the  exhaust  gases  from  the  main  engine 
for  the  purpose.  This  means  is,  however,  scarcely  practic- 
able, since,  especially  in  two-cycle  engines,  the  heat  available 
is  not  sufficient  for  the  work  it  has  to  accomplish,  though 
possibly  if  the  number  of  steam-driven  auxiliaries  be  limited 
to  the  winches  and  windlasses  it  might  be  feasible.  It 
has  to  be  remembered  also  that  some  auxiliaries  are  re- 
quired in  port,  particularly  for  loading  and  unloading 
cargo,  when  the  main  engine  is  standing,  and  hence  at  that 
time  the  boiler  must  necessarily  be  provided  with  fuel. 


DIESEL  ENGINES  FOR  MARINE  WORK         199 

This  aiTangement  of  the  retention  of  steam-driven  auxi- 
liaries and  the  provision  of  a  donkey  boiler  is  one  which, 
although  likely  to  find  very  \\dde  adoption,  may  only  be 
considered  as  a  temporary  measure  employed  in  certain 
cases  to  avoid  having  too  much  machinery  to  which  the 
marine  engineer  is  unaccustomed. 

There  is  moreover  the  objection  that  when  the  vessel  has 
left  port  and  begun  its  voyage  on  the  open  sea,  the  only 
steam  required  will  be  for  the  steering  gear  and  the  whistle, 
as  any  bilge  pumps,  etc.,  which  are  needed  can  be  operated 
direct  from  the  Diesel  engines  propelling  the  ships. 

For  this  reason  if  steam  auxiliaries  be  decided  upon  it  is 
desirable  that  some  simple  means  should  be  provided  for 
shutting  down  the  main  engines,  and  for  this  purpose  Mr. 
Reavell  has  worked  out  a  system  which  is  termed  the 
"  Duplex  Pressure  System,"  in  which  a  simple  compressor 
operated  from  the  engine  supplies  air  for  these  purposes,  the 
air  being  used  in  the  ordinary  t\^e  of  steam  steering  engine. 
This  Duplex  System  provides  for  two  pressures,  the  lower 
for  ordinary  work  and  the  higher  for  storage  purposes,  and  it 
is  automatically  controlled  so  that  the  compressor  for  storage 
purposes  has  no  load  thrown  upon  it  during  the  whole 
voyage,  unless  some  extra  demand  for  air  occurs  which 
exceeds  the  normal  supply.  A  simple  form  of  governor  is 
also  provided  for  the  compressor  for  supplying  the  normal 
air  for  steering,  so  that  when  the  demand  is  less  than  the 
capacity  of  the  compressor  it  is  drawn  out  of  action  in  a 
simple  manner. 

Such  an  arrangement  enables  the  steam  boiler  to  be  shut 
down  when  the  ship  has  left  port,  and  steam  need  not  be 
raised  again  until  reaching  harbour  at  the  end  of  the  voyage. 
All  that  is  necessary  is  to  close  the  steam  valve  to  the  deck 
machinery  and  to  open  the  air  valve  from  the  compressor, 
although  it  is  desirable  perhaps  to  arrange  for  some  of  the 
exhaust  gases  from  the  main  Diesel  engine  to  be  parsed 
through  the  auxiliary  steam  boiler  during  the  whole  voyage 
so  as  to  keep  the  water  at  boiling  point  and  enable  steam  to 
be  rapidly  raised  should  an  emergency  arise. 


200    DIESEL  ENGINES  FOR  LAND  AND  MARINE  WORK 

There  is  not  a  single  auxiliary  used  at  sea  which  has  not 
frequently  been  electrically  driven  in  steamships  "wdth  entire 
satisfaction,  and  hence  in  Diesel  shijDs  where  in  the  ordinary 
way  no  steam  is  available,  it  is  but  a  question  of  time  before 
all  auxiliaries  which  cannot  be  driven  directly  off  the  auxi- 
liary compressor  engine  will  be  operated  electrically  and 
take  their  power  from  the  main  dynamo.  The  question  as 
to  whether  the  dynamo  should  be  separately  driven  by 
another  Diesel  engine  or  off  the  auxiliary  compressor  engine 
depends  on  the  size  of  the  ship  and  the  corresponding  auxili- 
ary power  required,  but  as  the  auxiliary  compressor  is  out 
of  operation  for  long  periods,  reasons  of  economy  may  with 
safety  cause  the  latter  arrangement  to  be  adopted  even  in 
moderately  large  ships. 

Fuel  Consumption  of  Motor  Vessels. — Details  regard- 
ing the  fuel  consumption  of  Diesel  engines  have  been  given 
previously  for  various  types  of  motors,  but  it  can  be  readily 
understood  that  the  figures  that  are  obtained  on  the  test-bed 
are  not  exactly  those  met  with  in  the  course  of  operation 
in  the  ship.  The  best  conditions  of  operation  are  not  main- 
tained at  sea,  but  from  the  table  which  is  given  below  it  will 
be  seen  that  the  actual  consumption  on  a  commercial  scale 
varies  less  from  the  test  figures  than  does  that  of  a  corre- 
sponding steam  engine  in  a  steam  vessel.  Moreover,  it 
has  been  quite  clearly  proved  that  the  fuel  consumption 
decreases  to  a  marked  extent  after  a  Diesel  engine  has  been 
in  service  for  several  months,  so  that  this  compensates 
almost  entirely  for  the  higher  consumption  which  might 
be  anticipated  under  the  more  strenuous  working  condition. 
The  following  table  (p.  201)  gives  the  average  fuel  consump- 
tions which  have  been  obtained  with  various  motor  ships 
during  comparatively  long  periods,  and  whilst  they  cannot 
be  taken  as  representing  a  basis  of  comparison  between  the 
various  types  of  motors  (since  the  conditions  of  loading 
vary  considerably  and  there  are  other  circumstances  which 
would  have  to  be  taken  into  consideration),  they  neverthe- 
less give  a  very  close  approximation  to  the  consumption 
of  oil  which  will  be  obtained  with  any  class  of  motor  vessels. 


DIESEL  ENGINES  FOR   MARINE  WORK         201 


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202    DIESEL  ENGINES  FOR  LAND  AND  MARINE  WORK 

For  this  reason  they  are  valuable  for  purposes  of  comparison 
with  steam  vessels  doing  corresponding  work.  In  all 
instances  the  relative  fuel  consumption  of  oil  and  coal  for 
motor  and  steam  ships  respectively  which  were  given  pre- 
viously are  well  borne  out,  and  it  is  probable  that  in  most 
cases  a  corresponding  steamship  would  consume  about  4  to 
4|  times  the  weight  of  fuel  as  compared  with  a  motor 
vessel,  the  one  burning  coal  and  the  other  using  oil. 

Engine -Room  Staff  for  Motor  Ships. — The  staff 
required  in  the  engine-room  for  motor  vessels  is  consider- 
ably below  that  necessary  for  corresponding  steamships, 
being  usually  in  the  neighbourhood  of  two-thirds.  As, 
however,  it  is  mainly  the  cheaper  men  such  as  the  greasers 
who  are  dispensed  with,  it  does  not  mean  there  is  a  reduc- 
tion of  one-third  in  the  pay  bill,  one-quarter  probably  being 
a  nearer  figure.  As  instances  of  the  staff  required  in  various 
cases  may  be  cited  four  motor  vessels  in  which  two  engines 
each  of  850  H.P.  are  installed,  the  deadweight  capacity 
being  5,000  tons,  and  the  length  overall  just  over  370  feet. 
In  these  vessels  the  staff  consists  of  4  engineers,  3  assistant 
engineers,  3  greasers,  1  donkey  man  and  1  pump  man.  In 
another  motor  vessel  -iOO  feet  in  length,  having  two  Diesel 
engines  capable  of  developing  about  2,400  B.H. P.,  the  staff 
consists  of  4  engineers,  4  assistant  engineers  and  4  greasers, 
whereas  a  similar  steam  vessel  or  one  to  carry  the  same 
cargo,  which  in  this  case  is  about  7,500  tons,  would  require 
4  engineers,  1  apprentice,  1  pump  man,  1  donkey  man,  3 
greasers  and  16  firemen  and  trimmers. 

Weights  of  Marine  Diesel  Engines. — Though  it  is 
usually  accepted  that  the  weights  of  Diesel  engines  for 
marine  work  are  below  corresponding  steam  equipment, 
a  few  figures  may  be  given  showing  the  \\eights  of  actual 
installations.  As  a  generalization  it  may  be  taken  that 
for  powers  up  to  1,000  H.P.,  the  weight  inclusive  of  piping, 
starting  air  bottles,  manoeuvring  air  reservoirs,  with  the 
direct  driven  scavenge  pump  and  air  compressor,  and  also 
the  accessory  circulating  water  and  lubricating  pumps, 
is  in  the  neighbourhood  of  one  ton  to  every  10  B.H. P.  for 


DIESEL   ENGINES   FOR  MARINE   WORK 


203 


two-cycle  single-acting  motors,  whilst  a  four-cycle  engine 
would  in  general  be  15  to  20  per  cent,  heavier.  The  auxi- 
liary compressor,  which  is  practically  the  only  auxiliary 
in  addition  to  those  which  are  necessary  for  a  steam-driven 
ship,  would  add  some  8  to  10  per  cent,  to  the  weight. 

For  higher  powers  the  weight  per  horse  power  decreases 
unless  there  is  a  considerable  reduction  in  speed,  but  not 
to  a  very  large  extent,  and  a  4,000  H.P.  two-cycle  single- 
acting  marine  motor,  with  accessories  as  before,  weighs 
about  350  tons.  The  figures  are  naturally  only  approximate, 
and  for  moderate  speed  such  as  best  suit  conditions  and 
propeller  efficiency,  say  from  about  160  revolutions  per 
minute  in  the  smaller  engines  to  120  in  the  larger.  With 
double-acting  motors  the  weights  are  decreased,  though 
to  what  extent  it  is  difficult  at  present  to  estimate.  A 
12,000  B.H.P.  six-cylinder  double-acting  engine  should, 
however,  not  weigh  more  than  600  to  700  tons  complete. 

To  take  a  few  instances,  a  Sulzer-Diesel  marine  engine 
of  850  B.H.P.  at  160  revolutions  per  minute  weighed  77 
tons,  or  about  200  lb.  per  B.H.P.,  whilst  another  two-cycle 
single-acting  motor  of  2,000  B.H.P.  weighed  170  tons  or 
about  180  lb.  per  B.H.P.,  though  at  a  lower  speed  of  130 
revolutions  per  minute.  A  Krupp-Diesel  motor  of  1,250 
B.H.P.  at  140  revolutions  per  minute,  also  two-cycle  single- 
acting,  weighed  115  tons  or  about  210  lb.  per  B.H.P.,  whilst 
similar  slow-speed  engines  of  the  M.A.N,  type  work  out  as 
follows,  where  it  will  be  noticed  that  the  2,000  B.H.P. 
motor  is  relatively  heavier  than  the  1,2C0  B.H.P.  : — 


13.H.P. 

Revs,  per  Miii. 

Weight  in  Tons. 

Lbs.  par  B.H.r. 

1,200 
1,600 
2,000 

150 
120 
120 

91 
145 

178 

170 
200 
200 

The    Design    of    Large    Engines,    with    Particular 
Reference  to  the  Motor  Battleships. — In  view  of  the 


204    DIESEL  ENGINES  FOR  LAND  AND  MARINE  WORK 

probable  imminence  of  the  advent  of  the  motor  battleship, 
the  design  of  very  large  engines,  and  the  general  arrangement 
of  the  plant  which  is  to  be  anticipated,  may  be  discussed. 
There  is  little  doubt  that  a  triple  screw  arrangement  offers 
most  advantages,  particularly  from  the  point  of  view  that 
one  or  two  of  the  engines  may  be  shut  down  as  desired. 
For  the  moment  it  may  be  taken  that  each  engine  should 
be  capable  of  developing  20,000  H.P.  in  six  cylinders,  which 
is  in  excess  of  the  power  required  on  any  existing  battleship, 
excluding  battle  cruisers. 

It  is  doubtful  if  engines  of  this  power  will  be  built 
both  of  the  single  acting  and  double  acting  type  (necessarily 
two-cycle),  and  present  indications  point  to  the  utihzation 
of  double-acting  motors.  Such  large  motors  will  probably 
be  quite  separate,  and  also  the  air  compressors.  With 
regard  to  the  scavenge  pumps,  there  would  seem  to  be 
advantages  in  driving  these  direct  off  the  crank  shaft  of 
the  engine,  although  separate  operation  by  means  of  Diesel 
engines  may  also  be  adopted.  With  the  latter  arrangement, 
easy  regulation  of  the  quantity  of  air  would  be  possible. 

By  a  direct  drive  off  the  crank  shaft,  it  should  not  be 
understood  that  the  scavenge  pumps  are  coupled  imme- 
diately to  the  engine  shaft,  as  it  w^ould  be  preferable  to  ar- 
range them  some  distance  aft  of  the  main  engines,  in  separate 
chambers.  Not  only  does  this  allow  a  better  disposition 
in  the  engine  room,  but  it  permits  of  a  variation  in  the 
supply  of  scavenge  air  by  increasing  or  decreasing  the 
pressure  in  the  scavenge  pump  room. 

Each  engine  should  be  provided  with  its  own  air  com- 
pressor, and  as  these  can  be  of  such  size  that  two  are  sufficient 
for  the  requirements  of  three  engines,  there  is  no  need  for 
an  auxiUary  set.  There  would  be  ample  room  to  arrange 
these  parallel  to  the  main  engines  or  at  right  angles,  as 
probably  the  centre  engine  would  be  some  distance  aft  of 
the  two  outer  motors. 

Double-acting  engines  require  two  fuel  inlet  valves  at 
the  bottom  in  any  case,  because  of  the  piston  rod,  and  no 
doubt  there  will  always  be  two  for  the  top,  although  in 


Fio.  90.-2.0011  H.P.   Sinsjle  Cylinder  Two-Cycle  D.iuble-Actmg  Die,sp|    Ensim 


DIESEL  ENCJINES   FOR   MARINE   WORK         205 

single-acting  engines  it  is  quite  likely  that  only  a  single 
valve  will  be  employed  up  to  2,000  H.P.  Indeed,  some 
manufacturers  take  the  view  that  immediately  two  valves 
become  necessary,  the  limit  in  single-acting  engines  has 
been  reached. 

So  far  as  the  disposition  of  the  machinery  goes  with  such 
a  design,  there  seems  no  reason  to  anticipate  any  serious 
difficulties  either  in  battleships  or  large  liners.  There 
would  be  no  interference  with  the  gunnery  arrangements, 
and  the  length  of  engine  room  would  probably  be  little 
more  than  one-half  of  the  total  length  of  boiler  and  engine 
room  combined,  in  the  case  of  steam  plant,  whilst  the 
weight  should  be  30  per  cent.  less. 

There  are  apparently  no  unknown  factors  in  the  problem 
of  the  adoption  of  very  large  Diesel  engines  for  battleships 
and  the  biggest  merchant  vessels,  and  there  remains  solely 
the  question  of  application.  This,  however,  will  not  rest 
long  in  abeyance,  as  can  readily  be  gathered  by  the  wonder- 
fully rapid  progress  which  has  been  made,  and  the  now 
generally  accepted  opinion  that  the  Diesel  engine  is  the 
motor  of  the  future  for  marine  propulsion. 

In  Fig.  90  an  illustration  is  given  of  an  experimental 
two-cycle  double-acting  Diesel  engine  built  by  Messrs. 
Krupp,  designed  for  2,000  B.H.P.,  which  gave  considerably 
more  power  than  this.  Although  this  actual  motor  must 
not  be  taken  as  the  prototype  of  the  large  Diesel  engine, 
it  will  be  found  that  12,000  B.H.P.  motors  will  embody 
many  features  of  the  design,  one  of  which  is  the  operation 
of  the  valves  by  means  of  oil  under  pressure. 


CHAPTER  VII 

CONSTRUCTION    OF   THE   DIESEL   MARINE 
ENGINE 

TWO-CYCLE       ENGINE  :        SWISS       TYPE BELGIUM       TYPES 

SWEDISH      TYPE- -GERMAN      TYPES BRITISH      TYPES 

FOUR-CYCLE  ENGINE  :     DUTCH  TYPE^ — GERMAN    TYPES 

DANISH  TYPE RUSSIAN  TYPES SMALL  DIESEL  ENGINES 

Two -Cycle  Engine  :  Swiss  Type. — At  the  present  time 
the  engine  which  is  perhaps  finding  most  general  appKca- 
tion  for  marine  work  is  the  two-cycle  single  acting  type. 
With  the  marine  engine  there  are  more  differences  of  con- 
struction than  with  the  stationary  motor,  owing  to  the  intro- 
duction in  the  two-cycle  marine  engine  of  a  suitable  reversing 
and  regulating  arrangement.  The  small  engine  of  Messrs. 
Sulzer's  construction  is  of  the  two-cycle  single  acting  type, 
and  it  is  built  with  four  or  six  working  cylinders — a  small 
flywheel  being  provided.  The  cylinders  are  supported  by 
pillars  instead  of  the  usual  A  frame,  and  easily  removable 
covers  enclose  the  crank  chamber.  The  valves  (scavenge, 
fuel  and  starting)  are  arranged  in  the  cylinder  head,  but 
in  each  cylinder  two  scavenge  valves  are  fitted,  one  on  each 
side  of  the  fuel  valve,  as  shown  in  Fig.  91,  which  illustrates 
a  typical  engine  of  this  design.  By  this  means  relatively 
small  valves  are  permissible  to  allow  the  entrance  of  the 
large  amount  of  scavenging  air,  and  the  valve  bodies  are 
lighter  and  morp  easily  operated,  but  in  the  latest  designs 
scavenge  valves  are  omitted  altogether,  and  ports  are 
employed  at  the  bottom  of  the  cylinder. 

In  the  engine  illustrated  in  Fig.  91  there  is  one  double 
acting  scavenge  pump  in  line  with  the  working  cylinders, 

206 


CONSTRUCTION   OF   DIESEL  MARINE   ENGINE    207 


with  a  piston  diameter  of  nearly  double  that  of  the  latter. 
The  scavenge  air  is  delivered  into  the  long  cyhndrical 
receiver  seen  at  the  back  of  the  engine,  and  thence  to  the 
various  cylinders  through  the  valves.     The  burnt  gaseous 


208    DIESEL  ENGINES  FOR  LAND  AND  MARINE  WORK 


g 

'5b 


10^^ 


"^P^s^ 


CONSTRUCTION  OF  DIESEL  MARINE   ENGINE    209 


mixture  is  e  x- 
hausted  through 
longitudinal  ports 
at  the  bottom  of 
the  cyhnder  ar- 
ranged round  the 
whole  of  the  cir- 
cumference, into  a 
common  exhaust 
pipe  running  the 
length  of  the  en- 
gine and  thence 
to  the  silencer. 
A  two  stage  air 
compressor  is  pro- 
vided arranged  as 
shown  for  the 
supply  of  injec- 
tion air  and  for 
filling  the  com- 
pressed air  ve  sels 
with  air  required 
for  starting  and 
manoeuvring,  al- 
though  this 
method  is  not 
always  adopted, 
the  pumps  being 
placed  in  front  of 
and  behind  the 
scavenge  cylinder 
in  some  engines, 
being  then  driven 
by  links  off  the 
scavenge  p  u  m  p 
piston  rod.  The 
pumps  are  \\'ater 
cooled,       inter- 


210    DIESEL  ENGINES  FOR  LAND  AND  MARINE  WORK 

mediate  cooling  between  the  stages  being  also  arranged 
for. 

A  long  trunk  piston  is  employed,  serving  at  the  same  time 
as  a  crosshead,  and  in  the  larger  engines  this  piston  is  water 
or  oil  cooled.  Forced  lubrication  is  adopted  for  all  the  main 
bearings,  the  oil  pumps  being  driven  off  the  crank  shaft  at 
the  end  of  the  engine,  and  also  the  cooling  water  pump,  while 
a  thrust  block  is  arranged  on  the  engine  itself,  though  for 
large  powers  it  may  be  fixed  separately  on  the  propeller  shaft 
as  near  the  engine  as  convenient. 

The  operation  of  starting  and  reversing  the  engine  is 
carried  out  by  means  of  compressed  air.  The  cam  shaft 
is  first  put  into  the  position  in  which  the  cams  are  set  to 
operate  the  valve  levers  for  ahead  or  astern,  by  turning  a 
vertical  spindle  which  drives  this  cam  shaft,  this  operation 
being  performed  by  turning  the  hand  wheel  controlling 
the  engine.  By  a  further  rotation  of  the  hand  wheel  the 
spindle,  on  which  are  pivoted  the  levers  working  the  valves, 
first  brings  the  starting  valve  lever  into  operation,  thus 
running  up  the  engine  on  compressed  air,  and  then  the 
fuel  and  scavenge  valve  levers,  cutting  out  the  starting 
valve  at  the  same  time.  This  is  accomplished  by  having 
all  the  levers  mounted  eccentrically  on  the  pivot  spindle 
as  sho\^ii  in  Fig.  91.  The  engine  has  an  automatic  arrange- 
ment for  regulating  the  fuel  and  air  during  the  reversing 
period,  so  as  to  assure  the  correct  positions  of  the  fuel  inlet 
mechanism,  and  a  governor  is  also  provided  to  prevent  the 
motor  running  beyond  a  determined  maximum  speed  which, 
however,  is  only  likely  to  occur  in  the  event  of  a  propeller 
shaft  breaking  or  the  engine  racing.  The  actual  speed  is  con- 
trolled by  a  small  hand  lever  which  regulates  the  amount  of 
fuel  delivered  from  the  fuel  pumps  to  the  fuel  inlet  valves. 

This  type  of  motor  is  now  seldom  constructed  owing  to 
the  new  designs  that  have  been  brought  forward,  and  is 
chiefly  of  interest  as  showing  the  tendencies  in  construction 
in  the  earlier  machines  of  relatively  small  power.  It  was 
of  much  value,  however,  in  affording  experience  in  the 
operation  of  small  marine  motors. 


212    DIESEL  ENGINES  FOR  LAND  AND  MARINE  WORK 

Fig.  92  shows  the  general  arrangement  of  a  single  engine 
and  accessories  of  this  type  in  which  the  references  are  as 
follows  : — 

A  Engine  coupled  direct  to  propeller  shaft. 

BiB^BsBi  Working  cylinders. 

C  Scavenge  pump. 

Di  Suction  pipe  for  scavenge  air. 

D-i  Exhaust  pipe. 

El  Starting   and   manoeuvring   air  reservoirs. 

E2  Reserve  starting  air  reservoirs. 

E3  Ignition  air  reservoir. 

F1F2  Air  pumps. 

O1G2G3  Fuel  tanks, 

G4G5  Fuel  reservoirs. 

H  C^ooling  water  pump. 

This  is  a  typical  arrangement  which  has  been  adopted 
for  small  engines,  the  auxiliary  air  compressor  being  in- 
stalled in  any  convenient  position,  not  necessarily  in  the 
engine-room,  but  if  desired  at  some  portion  of  the  vessel 
above  the  water  line.  Fig.  93  shows  the  general  arrange- 
ment of  a  comparatively  small  Diesel  engine  plant,  installed 
as  an  auxihary  on  a  sailing  vessel,  in  which  the  compact- 
ness of  the  engine  and  its  accessories  is  well  seen.  The 
various  portions  will  be  understood  from  the  above  descrip- 
tion without  further  details. 

The  type  of  engine  adopted  by  Messrs.  Sulzer  for  sub- 
marines and  torpedo  boats  is  a  six-cylinder  machine  with 
two  scavenge  pumps  in  line  with  the  working  cylinders  and 
an  air  compressor  for  the  injection  and  starting  air  in  front 
of  each  scavenge  cylinder.  Figs.  94  and  95  show  respec- 
tively the  arrangement  of  the  engines  for  a  torpedo  boat  and 
a  submarine — the  engines  being  staggered  owing  to  the 
restricted  width  of  the  engine-room. 

In  their  most  recent  design  of  marine  engine  particu- 
larly adapted  for  large  cargo  vessels,  Messrs.  Sulzer  Bros, 
have  made  several  important  modifications  in  design,  and 


214 


CONSTRUCTION  OF  DIESEL  MARINE  ENGINE    215 


Figs.  97,  98,  102  illustrate  the  present  construction  for 
slow  speed  engines  of  high  power.  The  two-cycle  prin- 
ciple is  retained,  and  the  main  point  of  difference  lies  in 


216     DIESEL  ENGINES  FOR  LAND  AND  MARINE  WORK 

the  abolition  of  all  scavenge  valves  in  the  cylinder  cover, 
the  actual  method  of  scavenging  being  described  later. 

For  sizes  up  to  800—1,000  H.P.  a  four-cylinder  design  is 
employed,  engines  of  SCO  B.H.P.  for  a  vessel  of  the  Hamburg 
South  American  Line  having  a  cylinder  diameter  of  16J 
inches  and  a  stroke  of  27  inches,  the  speed  of  revolution 
being  150  at  maximum  output.  The  engine  is  of  the  cross- 
head  type,  and  although  the  crank  chamber  is  enclosed, 
it  is  provided  with  covers  at  the  back  which  are  readily 
removable.  The  arrangement  of  the  scavenge  pump  differs 
from  that  adopted  by  Messrs.  Krupp  and  Messrs.  Carels  for 
similar  slow  speed  two-cycle  marine  engines.  Only  one 
pump  is  provided  for  each  engine,  and  this  is  driven  direct 
off  the  crank  shaft,  being  mounted  on  the  same  bed-plate 
at  the  after  end.  The  low  pressure  stage  of  the  injection 
air  pump  forms  the  crosshead  for  the  scavenge  pump  piston, 
and  there  is  a  certain  advantage  in  this  arrangement  in  mini- 
mizing the  vibration  which  otherwise  occurs  due  to  the  heavy 
scavenge  pump  piston.  The  high  and  intermediate  pressure 
stages  of  the  air  pump  are  mounted  in  front  of  the  scavenge 
pump,  and  are  actuated  by  means  of  a  rocking  lever  from 
the  connecting  rod  of  the  low  pressure  pump. 

The  method  is  illustrated  in  Fig.  99,  in  which  both 
the  high  and  intermediate  stages  of  the  three-stage  compres- 
sor set  are  mounted  in  front  of  the  scavenge  cylinder.  The 
drive  is  arranged  from  a  crank  fixed  to  the  main  crank  shaft, 
and  as  is  seen  from  the  illustration,  the  piston  of  the  L.P. 
pump  forms  the  crosshead  of  the  scavenge  pump.  The 
general  arrangement  is  evident  from  the  diagram  and  need 
not  be  further  explained.  The  scavenge  pump  is  controlled 
by  a  piston  valve  as  seen  in  Fig.  98,  and  the  gear  on  the 
extreme  left  shows  the  Stephenson  link  motion  for  reversing 
the  delivery  of  the  scavenge  air  when  the  engine  is  reversed. 

Fig.  100  shows  diagrammatically  the  method  adopted 
for  the  supply  of  scavenge  air  to  the  engine  cj^hnders. 
Ports  are  provided  at  the  bottom  for  the  discharge  of  the 
exhaust  gases,  as  in  all  two-cycle  engines,  these  extending 
only  haK-way  round  the  periphery  and  being  represented 


Fig.  99. — Arrangement   of   Scavengo    Pump    and   Air   Compressor   with 

Sulzer  Marine  Engine. 

217 


Fig.  100. — Scavenging  Arrangements  by  means  of  Ports  in  Siilzer  Engine. 

218 


COXSTRUf'TTOX   OF   DIESEL   :\rARlXE   EXGIXE    219 

in  the  illustration  by  A,  the  discharge  into  the  exhaust  pipe 
taking  place  through  B.  The  scavenge  air  is  delivered  into 
the  pipe  C  from  the  scavenge  pump,  and  the  main  supply 
enters  the  cylinder  through  the  ports  D,  Avhich  are  spaced 
half-way  round  the  periphery  and  are  inclined  so  as  to 
deflect  the  air  upwards. 

In  the  actual  scavenge  pipe  itself  is  arranged  a  piston 
valve  actuated  directly  from  the  cam  shaft  by  means  of 
the  eccentric  E.  The  air  which  passes  through  this  valve 
enters  the  cylinder  through  the  ports  F,  which  extend  round 
one-half  of  the  circumference  and  are  immediately  above 
the  main  scavenge  ports.  The  opening  of  the  piston  valve 
is  so  arranged  that  air  is  introduced  through  the  slots  F 
after  the  ports  D  have  been  closed  by  the  main  piston  start- 
ing on  its  upward  stroke.  By  this  arrangement  the  scaveng- 
ing appears  to  be  very  effective,  and  it  is  of  interest  to  note 
that  so  many  different  methods  of  overcoming  the  undoubted 
difficulties  of  thoroughly  efficient  scavenging  have  been 
adopted  in  varying  designs.  There  is,  of  course,  the  advan- 
tage that  the  air  remaining  in  the  cylinder  after  scavenging 
is  at  a  pressure  of  about  3  lbs.  per  square  inch  instead  of 
at  atmospheric  pressure. 

As  no  valves  are  employed  in  the  cylinder  head  for 
exhaust  or  scavenge  air,  there  remain  but  the  fuel  inlet 
valve  and  the  starting  air  valve.  Reversing  is  thus  simpli- 
fied and  is  accomplished  merely  b}^  turning  the  cam  shaft 
through  an  angle  relative  to  the  crank  shaft  and  so  setting 
the  cams  operating  the  fuel  inlet  valve  in  a  position  for 
reverse  running.  This  operation  is  carried  out  by  raising 
the  vertical  intermediate  shaft  which  drives  the  cam  shaft 
from  the  crank  shaft.  This  intermediate  shaft  is  broken, 
and  a  sleeve  coupling  interposed,  which  permits  of  its  being 
raised  or  lowered,  and  thus  turning  the  cam  shaft  relative 
to  the  crank  shaft.  As  previously  mentioned,  the  scavenge 
air  supply  is  changed  on  reversal  by  means  of  a  Stephenson 
link  motion. 

From  the  illustrations  of  the  engine,  and  in  particular 
from  Fig.  97,  it  can  be  seen  that  there  are  two  hand  wheels 


220  DIESEL  ENGINES  FOR  LAND  AND  MARINE  WORK 

A  and  B  in  the  centre,  which  serve  for  reversing  and  manceu- 
vring  the  engine  by  hand,  in  the  event  of  the  breakdown 
in  the  auxihary  air  motors,  by  means  of  which  the  operations 
are  visually  carried  out.  The  levers  C  and  D  below  the 
wheels  A  and  B  respectively  control  these  servo  motors, 
the  first  (operated  by  D)  being  for  the  purpose  of  reversing 
the  link  motion  of  the  ports  for  the  scavenge  pump,  and 
also  rotating  the  cam  shaft,  whilst  the  second  (operated 
by  C)  controls  the  starting  and  fuel  valve  levers  for  starting 
and  running. 

The  reversmg  may  be  followed  out  in  stages.  In  the  first 
place  the  scavenge  pump  valve  has  to  be  reversed,  and  the 
link  motion  previously  mentioned  is  changed  over  by  means 
of  the  horizontal  shaft  E  (Fig.  102).  A  partial  rotation 
of  this  shaft  causes  the  link  to  reverse,  and  the  rotation  is 
given  it  by  the  compressed  air  auxiliary  motor  controlled 
by  lever  D  on  the  hand  wheel  B.  The  same  operation  of 
this  motor  causes  the  cam  shaft  to  be  turned  through  a 
small  angle  relative  to  the  crank  shaft. 

As  regards  the  valves,  there  is  but  one  cam,  F,  for  the 
fuel  valve,  both  for  ahead  and  astern,  and  as  in  reverse 
running,  all  that  is  required  is  a  change  of  lead  from  one 
side  of  the  dead  point  to  the  other,  it  is  evident  that  the 
rotation  of  the  cam  shaft  is  sufficient  to  provide  this  with 
one  cam.  The  fuel  valve  cam  is  thus  set  for  reverse  running 
by  the  partial  rotation  of  the  cam  shaft.  This,  however, 
would  not  set  the  air  starting  valves  correctly  for  astern 
running,  as  the  leads  are  different,  and  hence  two  cams  are 
provided  for  each  of  these  valves.  These  are  fixed  side 
by  side  on  the  cam  shaft  {G  and  H),  and  as  there  is  no  longi- 
tudinal motion  of  this  shaft  in  reversing,  as  in  most  other 
engines,  arrangements  have  to  be  made  for  bringing  the 
starting  air  valve  levers  over  the  astern  or  ahead  cam  as 
required.  This  is  carried  out  by  having  a  vertical  rod  J 
attached  to  the  air  valve  cam,  at  the  bottom  of  which  is 
the  roller  which  is  lifted  by  the  cam.  The  joint  of  the 
vertical  rod  and  the  valve  lever  is  a  double  one,  and  allows 
the  former  to  move  longitudinally  so  as  to  bring  the  roller 


222  DIESEL  ENGINES  FOR  LAND  AND  MARINE  WORK 

above  one  or  other  cam.  The  longitudinal  motion  is  given 
to  the  shaft  K  from  the  auxiliary  air  motor  controlled  by 
lever  C  at  the  starting  platform,  the  roller  being  coupled 
to  this  shaft  K  by  means  of  a  small  connecting  rod. 

When  starting  up,  the  air  valve  levers  (or  rather  the  verti- 
cal rods  attached  to  them)  are  brought  down  on  the  cams  by 
a  rotation  of  the  spindle  L,  on  which  the  levers  are  pivoted, 
this  operation  also  being  controlled  by  the  auxiliary  air 
motor  from  the  starting  platform  by  the  lever  C.  The 
engine  runs  up  on  air,  the  fuel  valve  levers  being  out  of 
action  for  the  time  being.  When  the  engine  has  run  up 
to  speed  after  a  few  revolutions,  the  air  valve  levers  are 
Hfted  up  and  the  fuel  valves  come  into  operation,  and  the 
arrangement  is  such  that  the  engine  can  run  (1)  with  only 
two  cylinders  on  air,  (2)  with  four  cylinders  on  air,  (3)  with 
two  cylinders  on  air  and  two  on  fuel,  and  finally,  (4)  with 
four  cylinders  on  fuel.  The  dial  seen  in  the  centre  of  the 
engine  in  Fig.  102  indicates  how  the  cylinders  are  working 
in  this  respect.  In  order  that  this  arrangement  may  be 
carried  out,  the  spindle  L  on  which  the  valve  levers  are 
pivoted  is  divided  in  two  portions  in  the  centre,  so  that  two 
of  the  air  valve  levers  may  be  down  on  their  cams  on  two 
cylinders  and  two  of  the  fuel  valve  levers  on  the  remaining 
two  cyUnders. 

The  quantity  of  fuel  admitted  to  the  cylinder  is  controlled 
by  means  of  the  lever  M  seen  in  Fig.  100  in  the  centre  of 
the  engine,  whilst  the  air  injection  pressure  is  also  regulated 
from  the  starting  platform,  being  about  60  atmospheres  for 
full  speed  and  4.0  atmospheres  for  slow  running.  Four 
fuel  pumps  are  provided  at  N,  one  for  each  cylinder,  and 
the  supply  to  each  cyhnder  may  be  regulated  by  hand. 
The  lever  seen  in  front  of  the  fuel  pump  chamber  is  for 
pumping  up  the  fuel  before  starting.  The  governor  O 
is  also  connected  to  the  fuel  chamber  by  the  vertical  rod  P, 
so  that  when  the  speed  exceeds  the  normal,  the  supply  is 
reduced. 

An  interesting  feature  of  the  design  of  the  engine  is  the 
control  of  the  timing  of  the  fuel  valve  at  varying  speeds. 


= 

p.; 

i; 

[To  /ace  page  222 


r^\ 


[To  fare  page  222. 


Fin.    IIK),— Siilzor  T%v..-C'.vcl,'  Suhninrinc  Motor  of  IJOU  JVH.l'. 


[To  lure  fine  222 


CONSTRUCTION   OF  DIESEL   MARINE   ENGINE    223 

This  is  accomplished  by  means  of  the  hand  wheel  P,  which 
turns  the  shaft  R  and  moves  the  vertical  rod  8  connected 
to  the  fuel  valve  cam  out  of  the  vertical,  so  that  the  timing 
of  its  contact  with  the  fuel  valve  cam  is  altered  as  required. 

The  various  pumps  seen  in  front  of  the  engine  are  for 
auxiliary  purposes.  Forced  lubrication  is  adopted  and 
the  oil  is  used  continuously,  being  cooled  in  circulation.  For 
the  cylinder  lubrication  eight  small  pumps  are  provided,  two 
for  each  cylinder,  alloA\ing  four  points  in  which  the  lubricat- 
ing oil  may  enter  each  cylinder.  The  pistons  are  water 
cooled,  a  tube  being  attached  to  the  hollow  body  of  the  piston, 
which  dips  into  a  water  reservoir,  forcmg  the  water  up  into 
the  piston.  The  exhaust  pipe  is  also  water  cooled,  and 
the  cylinder  jacket  cooling  is  carried  out  in  the  usual  way. 

The  fuel  consumption  of  the  engine,  with  all  the  auxiliary 
pumps  as  shown,  is  0*46  lbs.  per  B.H.P.  hour,  and  the  weight 
of  the  engine  without  any  auxiharies  is  55  tons.  Including 
all  pipes,  air  reservoirs,  silencers,  etc.,  the  weight  is  77  tons, 
and  the  fly-wheel  weighs  9i  tons. 

Belgian  Types. — In  Belgium  the  Diesel  engine  has  been 
mainly  developed  by  Messrs.  Carels  of  Ghent,  and  the 
original  marine  motor  of  this  firm  did  not  differ  greatly 
from  that  of  the  earlier  types  of  Messrs.  Sulzer's,  as  described 
previously.  Fig.  104  shows  one  of  the  first  large  marine 
engines  (of  1,000  B.H.P.)  of  four  working  cylinders  and 
one  scavenge  pump,  this  motor  now  being  utilized  for  experi- 
mental work  and  for  dynamo  driving.  Although  con- 
taining many  features  which  are  not  now  considered  the 
best  practice,  the  engine  was  a  remarkable  achievement 
in  that  it  was  by  far  the  largest  directly  reversible  two- 
stroke  machine  built  at  the  time. 

The  marine  engine  which  has  now  been  developed  at 
Ghent  for  general  ship  propulsion,  and  which  is  constructed 
by  a  number  of  firms,  is  of  a  different  type,  based  on  the 
experience  gained  with  the  earlier  motors.  The  general 
type  is  illustrated  in  Fig.  108,  whilst  i^ig'.  Ill  shows  an 
1,800  H.P.  engine  for  a  large  oil  tank  vessel.  Crossheads 
are  employed  and  the  design  is  of  the  open  type  with  a  view 


CONSTRUCTION   OF  DIESEL  MARINE  ENGINE    225 

to  conforming  to  the  ideas  of  marine  engineers,  and  to 
render  the  parts  accessible.  There  are  four  or  six  cylinders 
according  to  the  size,  and  generally  speaking  the  engine 
is  a  four-cylinder  one  up  to  about  1,000  or  1,200  H.P.,  and 
six  cylinders  if  above.  Two  scavenge  pumps  are  always  em- 
ployed, which  is  a  point  of  difference  from  the  Sulzer  motor. 
These  scavenge  pumps  are  arranged  at  the  back  of  the 
engine  and  driven  off  the  crossheads  of  two  of  the  cylinders 
by  means  of  connecting  rods,  in  much  the  same  way  as  the 
air  pumps  on  some  reciprocating  steam  engines.  A  Reavell 
compressor  is  arranged  at  the  end  of  the  engine  in  the  same 
manner  as  in  many  types  of  stationary  Diesel  engines.  The 
scavenge  pumps,  which  are  double  acting,  are  provided  with 
piston  valves — a  method  which  seems  well  adapted  for  the 
purpose. 

Usually  the  bed-plate  is  divided  into  two  or  three  portions, 
and  the  frame  is  built  up  by  hollow  box  columns,  on  the 
top  of  which  the  cylinders  are  supported,  there  being  two 
columns  for  each  cylinder.  Several  of  these  columns  (usu- 
ally four)  are  employed  for  the  purpose  of  conveying  the 
scavenge  air  to  the  main  scavenge  pipe,  thus  reducing  the 
complication  of  piping  on  the  engine.  The  crank  shaft  is 
also  divided,  and  this  is  of  advantage  in  that  a  smaller  spare 
length  may  be  carried  in  the  vessel. 

In  large  two-cycle  marine  engines  the  question  of  scaveng- 
ing is  one  of  some  difficulty.  A  big  volume  of  air  at  low 
pressure  has  to  be  admitted,  and  it  is  impossible  to  accom- 
plish this  by  means  of  one  valve  only,  when  valves  are 
employed.  In  the  Carels  engine  for  large  powers,  four 
scavenge  valves  are  fitted  to  each  cylinder,  arranged  in  the 
cover  and  operated  by  two  levers  and  two  cams.  The 
method  is  somewhat  expensive,  and  to  a  certain  extent 
complicated,  and  largely  minimizes  the  advantage  of  sim- 
plicity which  the  two-cycle  engine  might  otherwise  claim 
over  the  four-cycle,  but  it  ensures  very  efficient  scavenging. 

In  spite  of  the  many  valves  necessitated  by  this  arrange- 
ment, reversing  is  very  rapidly  carried  out,  the  time  taken 
from  full  speed  ahead  to    full  speed  astern  being  about 

Q 


226  DIESEL  ENGINES  FOR  LAND  AND  MARINE  WORK 

10  seconds.  The  general  principle  of  the  method  of  revers- 
ing is  to  provide  a  separate  ahead  and  astern  cam  side  by 
side,  both  for  the  fuel  valve  and  the  starting  valve,  and 


only  one  cam  for  each  pair  of  scavenge  valves.  It  is  evident 
that  as  far  as]  the  actuation  of]  these  valves  is  concerned, 
this  arrangement  is  sufficient  if  the  cam    shaft  is  turned 


CONSTRUCTION   OF  DIESEL  MARINE   ENGINE    227 

through  a  certain  angle  relative  to  the  crank  shaft.  When 
the  engine  runs  in  the  astern  direction,  the  scavenge  valves 
will  be  opened  at  the  correct  moment  for  reverse  running. 


ria  ^z 


-A» 0^! -I 


I"    s 


The  turning  of  the  cam  shaft  is  accomplished  by  means 
of  the  vertical  intermediate  shaft  seen  in  the  centre  of 
Fig.  108,  by  which  the  cam  shaft  is  driven  from  the  crank 
shaft  as  in  stationary  engines.     This  vertical  shaft  is  raised 


228  DIESEL  ENGINES  FOR  LAND  AND  MARINE  WORK 

either  by  means  of  the  large  hand  wheel  in  the  left  of  Fig. 
108,  or  by  means  of  a  small  compressed  air  motor.  It  is 
in  two  parts  coupled  by  a  sleeve,  and  only  the  upper  portion 
is  raised,  thus  carrying  the  cam  shaft  round  through  the 
required  angle. 

The  operation  just  described  sets  the  scavenge  valve  cams 
in  their  correct  positions.  For  the  fuel  and  starting  valve 
cams,  since  the  cam  shaft  is  not  capable  of  moving  longi- 
tudinally, a  secondary  or  manoeuvring  shaft  is  provided 
in  front  of  the  cam  shaft.  When  it  is  desired  to  reverse 
the  engine,  this  manoeuvring  shaft  is  moved  lengthwise 
a  distance  equal  to  the  width  of  one  of  the  cams,  and  by 
this  means  the  rollers  of  the  levers  actuating  the  valves 
are  caused  to  come  over  the  astern  cams  instead  of  the  ahead. 
Before  this  can  be  done,  however,  the  levers  have  all  to 
be  lifted  off  the  cams  so  that  the  movement  may  be  given 
to  the  manoeuvring  shaft.  The  whole  of  the  actions  for 
reversing  or  starting  up  the  engine,  except  turning  the  cam 
shaft,  as  described  previously,  are  accomphshed  by  means 
of  the  handwheel  seen  in  the  centre  of  Fig.  108,  which 
causes  the  manoeuvring  shaft  to  rotate.  After  the  cams 
are  set,  the  engine  is  started  upon  air,  then  some  of  the 
cylinders  run  on  air  and  some  on  fuel ;  in  the  third  stage 
all  starting  air  is  cut  off,  and  finally  all  the  cylinders  are 
in  operation  running  on  fuel.  The  various  levers  and  handles 
are  interlocked,  so  that  it  is  impossible  for  the  engine  to  start 
up  until  the  cams  are  in  their  correct  positions,  and  no 
fuel  can  be  supplied  to  the  engine  until  it  has  run  up  on 
compressed  air.  The  sloping  handwheel  seen  on  the  right 
in  Fig.  108  is  for  controlling  the  governor,  which  is  of  the 
centrifugal  type  and  acts  on  the  fuel  pumps  to  regulate  the 
speed  of  the  engine. 

The  pistons  are  of  cast  iron  and  are  water  cooled,  whilst 
the  cylinder  covers  are  of  cast  steel.  The  exhaust  ports 
are  at  the  bottom  of  the  cyhnders,  and  a  stuffing  box  is 
fitted  at  the  bottom  to  prevent  leakage  of  exhaust  gases 
into  the  engine-room. 

Figs.  113  and   114  show  an  engine  of  this  type  of  800 


Fig.  1 


Fic.   I(n._l.r,l)ll  B.HI'.  CureU  Tviio  .Murine  Mi 


Eml  View,  sliowing  Scavenge  Pump. 
[Tojacc  pagei 


1F7  n—i' 


\®    0 


'f     I 


[To  face  page  228. 


Fig.   108.— Marine  Diesd  Engine,  Carels  Type. 


m 


le  Engine. 


Scavenginj  Puerp 


Steer  ng  Compressor 
Bilge  Pump 


Fui.   ]0n.— Plan  of  1,500  H.P.  Carels  Marine  Engi 


[To  face  page  228. 


'ype)- 


Fio.  110.— Sectional  Elevation  of  1,500  H.P.  Carels  MarineJM.itor  (New  'S^y). 


[To  lace  page  228. 


[Tu  Jure    iMUJi     -l-l^. 


Fio.    112.-  l.tllll  H.l'.  faiPb-Ti-cklenbi.rg  M»iim.  E.igii 


CONSTRUCTION  OF   DIESEL   MAIUNE   ENGINE    220 


B.H.P.  built  by  Messrs.  Richardson,  Westgarth  &Co.,  Ltd., 
whilst  Fig.]]  2  represents  a  similar  motor  of  1,500  B.H.P. 


built   by  the    Tecklenborg  Co.     of    Bremerhaven    for    tlie 
motor  ship  Rolandsecl- . 

Cockerill    Engine. — In    conjunction    with    Dr.    Diesel, 


230  DIESEL  ENGINES  EOR  LAND  AND  MARINE  WORK 

Messrs.  CockeriU,  of  Seraing,  have  produced  a  design  of  en- 
gine which  is  built  in  relatively  large  sizes,  and  is  indeed  not 
specially  suited  for  smaller  motors.  It  is  of  the  two-cycle 
eingle-acting  type,  but  up  to  the  present  the  engines  which 
have  been  constructed  have  been  non-reversible,  although 
directly  reversible  motors  are  now  being  built.  The  reason 
for  the  adoption  of  a  non-reversible  type  was  solely  on 
account  of  the  ship  in  which  the  engines  were  installed  being 
destined  for  West  Africa,  and  the  consequent  desirability 
of  the  absence  of  as  many  new  features  as  possible. 

In  the  arrangement  of  the  motor  of  650  B.H.P.  at  280 
revolutions  per  minute,  there  are  four  working  cylinders 
with  a  scavenge  pump  at  each  end.  Outside  each  of  these 
are  the  high  and  intermediate  pressure  stages  of  the  air 
pumps  for  injection  and  starting  air,  the  low  pressure  stages 
being  above  the  scavenge  pumps — a  method  by  which  it 
is  believed  a  smoother  running  may  be  obtained.  The 
object  is  for  the  air  pump  to  act  as  a  sort  of  damper  to 
the  scavenge  pumps,  and  this  arrangement,  or  one  of  similar 
principle,  has  also  been  adopted  in  other  designs. 

The  engine  is  of  a  type  in  which  scavenging  is  accom- 
plished by  means  of  ports  in  the  cyhnder.  In  order  to 
avoid  the  necessity  either  of  cutting  away  the  piston  to 
deflect  the  scavenge  air  towards  the  top  of  the  cylinder, 
as  in  the  case  of  the  Polar  Diesel  engine,  or  utiUzing  an 
auxihary  scavenging  valve,  as  is  done  by  Messrs.  Sulzer, 
the  scavenge  ports  are  themselves  shaped  vdth  the  idea  of 
causing  the  air  to  clear  the  whole  of  the  cylinder  effectively. 

These  ports  occupy  rather  more  than  half  of  the  circum- 
feren:e  of  the  cylinder,  leaving  therefore  less  than  one-half 
for  the  exhaust  ports.  There  are  two  sets,  one  pair  being 
arranged  tangentially,  so  that  the  air  entering  them  sweeps 
round  the  walls  and  rises  to  the  top  of  the  cyhnder,  whilst 
the  other  pair  cause  the  air  to  rise  right  to  the  centre.  By 
this  method  there  is  probably  an  economy  in  the  quantity 
of  air  necessary  to  give  complete  scavenging. 

In  the  cover  of  each  cylinder  there  are  two  valves — the 
fuel  inlet   valve  and  the  starting  air  valve.     The  motor 


CONSTRUCTION  OF  DIESEL  MARINE  ENGINE    231 


Fig.    114. — End  View  of  800  H.P.  Carels'  Tj-pe  Two-Cycle  Marine  Motor. 


is  of  the  enclosed  chamber  type  with  forced  hibrication, 
and  a  trunk  piston  is  employed,  which  is  quite  suitable 
for  powers  of  the  motors  such  as  have  up  to  the  present 
been  constructed. 


232  DIESEL  ENGINES  FOR  LAND  AND  MARINE  WORK 

Swedish  Type. — tSome  manufacturers  of  the  two-stroke 
engine  make  use  of  the  scavenge  air  cyhnders  for  starting 
and  reversing,  with  the  object  of  doing  away  with  the  neces- 
sity of  the  starting  valves  on  the  cylinders.  An  engine 
of  this  construction,  if  it  is  provided  with  ports  at  the  bot- 
tom of  the  cylinders  for  both  the  exhaust  and  the  scavenge 
air,  is  thus  simplified  to  the  extent  of  having  only  one  valve 
to  be  operated  in  the  cylinder  cover — namely  the  fuel  inlet 
valve,  and  a  very  convenient  reversing  gear  can  be  designed. 
The  Aktiebolaget  Diesels  Motorer  of  Stockholm  have 
developed  an  engine  on  these  lines  for  power  up  to  1,000 
I.H.P.  It  is  usually  constructed  with  four  working  cyhn- 
ders and  two  scavenge  air  cylinders  mounted  on  the  same 
bed-plate,  in  a  line  with  the  engines.  During  the  ordinary 
running  of  the  engine  the  air  from  the  two  scavenge  pumps 
is  delivered  into  the  receiver,  and  as  the  pumps  are  double 
acting  and  have  their  cranks  set  at  90°  a  very  regular 
supply  is  obtained.  The  air,  which  is  drawn  into  the  cylin- 
ders from  the  atmosphere  before  compression,  is  delivered 
from  the  receiver  into  the  various  working  cylinders  as 
the  scavenge  ports  are  uncovered  by  the  pistons,  the  pres- 
sure of  the  scavenge  air  being  approximately  the  same  as 
that  with  most  other  two-stroke  engines,  namely  about 
3  lb.  per  sq.  inch  above  atmosphere.  The  scavenge  or 
manoeuvring  cylinders,  as  they  may  also  be  called,  run  as 
compiessec^ir  engines  during  the  periods  of  starting  and 
reversing  these  engines,  but  as  air  is  only  employed  for  this 
purpose  for  two  or  three  revolutions  there  is  not  a  heavy 
call  on  the  air  receivers  in  which  compressed  air  is  stored  for 
carrying  out  these  operations.  The  starting  and  manoeu- 
vring receivers  (of  which  there  is  usually  one  main  and  one 
auxiliary)  are  replenished  by  means  of  a  special  pump 
which  may  be  situated  on  the  top  of  one  of  the  scavenge 
cylinders,  or  in  any  other  convenient  manner.  The  valves 
are  arranged  so  that  whenever  the  air  in  the  receivers  falls 
below  a  certain  predetermined  limit,  the  pump  immediately 
begins  to  charge  them  until  the  requisite  pressure  is 
reached.     The  compressed  air  for  injecting  the  fuel  into  the 


^- 


F    =Silniar. 

J    =Tool  Cheat. 

K  =Air  Inlet  Pipe. 

L    =  Exhaust  Pipe. 

H   ^Cooling  ll'oKr  Pump. 

Ni=Bilge  Pump. 

N,=OU  Pump. 

A,=Hand  Air  Pump. 


Flo.   115 — General  Arrangement  of  Engi 


CONSTRUCTION   OF   DIESEL  IMARTNE  ENGINE   233 

working  cylinders  is  provided  from  another  compressor, 
and  the  usual  type  of  vertical  cylindrical  air  reservoir  is 
employed  to  store  this  air.  A  separate  fuel  pump  is  fitted 
for  each  cylinder,  and  the  type  of  fuel  inlet  valve  and  pulver- 
iser described  and  illustrated  in  an  earlier  chapter  is  em- 
ployed, being  the  same  as  for  the  stationary  engine. 
These  pumps  work  generally  on  the  principle  commonly 
adopted  for  Diesel  engines,  but  as  there  is  no  governor  the 
opening  of  the  suction  valves  is  not  automatically  controlled. 
The  pumps  are  operated  by  links  which  receive  their  motion 
from  the  main  cam  shaft,  and  are  pivoted  eccentrically  on 
a  spindle  which  can  be  turned  by  hand,  thus  altering  the 
positions  of  the  links  relative  to  the  cam  and  so  varying 
the  opening  of  the  suction  valves.  This  in  turn  controls 
the  amount  of  fuel  admitted  to  the  cylinder  and  hence  the 
speed  of  the  engine.  For  reversing,  a  second  or  reverse  set 
of  cams  is  provided  on  the  cam  shaft,  which  is  moved  hori- 
zontally until  these  cams  come  beneath  the  levers  operating 
the  fuel  inlet  valves,  which  thus  open  at  the  required  point 
for  reversing.  The  valves  of  the  scavenge  pumps  which 
are  worked  by  eccentric  rods  are  also  reversed,  and  their 
eccentrics,  together  with  the  eccentrics  for  driving  the  fuel 
pumps,  are  mounted  on  a  separate  horizontal  spindle,  wiiich 
in  reversing  does  not  move  in  a  longitudinal  direction. 
When  the  reversing  handle  is  put  in  the  "  astern  "  position 
the  fuel  pump  is  unable  to  deliver  any  more  oil  to  the  cylin- 
der, and  the  fuel  valve  levers  take  up  thepositionsforreverse 
running  after  the  last  charge  of  oil  has  been  injected  into 
the  cylinders.  This  is  arranged  by  the  fuel  valves  being 
provided  with  wider  cams  than  the  regulating  arrangement 
for  the  pump,  so  that  the  fuel  valve  opens  for  one  revo- 
lution after  the  pump  has  been  out  of  operation.  The 
scavenge  cylinders  absorb  the  energy  of  the  flywheel  by 
running  as  pumps,  and  when  the  engine  comes  to  a  standstill 
the  scavenge  valves  are  in  such  positions  as  to  allow  com- 
pressed air  to  enter  from  the  receiver,  and  the  pumps  then 
run  as  motors.  The  fuel  pumps,  immediately  upon  the 
engine  starting,  force  oil  up  to  the  fuel  valves,  which  open 


234  DIESEL  ENGINES  FOR  LAND  AND  MARINE  WORK 

at  the  required  moments,  so  that  the  engine  when  starting 
up,  receives  two  impulses — one  from  the  scavenge  pumps 
operating  as  motors  and  then  later  from  the  fuel  injection, 
which  is  of  great  value  in  accelerating  the  speed  at  the  begin- 
ning. The  scavenge  pumps  after  one  or  two  revolutions 
as  air  motors  take  up  their  ordinary  work.  One  of  the  first 
British  ocean-going  motor  vessels  was  the  Toiler,  a  boat  of 
2,000  tons,  built  by  Messrs.  Swan,  Hunter  &  Wigham 
Richardsort,  equipped  with  two  engines  of  this  construction, 
each  of  180  H.P.  She  made  a  successful  voyage  across  the 
Atlantic  in  1911.  In  the  Toller  the  steering  gear,  windlass, 
and  auxihary  pumps  are  all  driven  by  compressed  air, 
and  a  separate  small  Diesel  engine  driven  compressor 
is  provided  for  this  work ;  but  as  at  sea  only  the  steering 
gear  is  usually  required,  the  compressed  air  is  then  taken 
direct  from  the  main  engine  and  the  auxiliary  plant  is 
shut  down.  Independent  tests  have  recently  been  carried 
out  on  several  of  these  engines,  with  a  view  to  ascertain- 
ing the  fuel  consumption  at  full  load,  the  results  of  which 
are  most  interesting  in  comparison  with  the  consump- 
tion of  the  ordinary  four-cycle  engine,  and  from  the 
figures  obtained  it  appears  that  the  difference  is  extremely 
small.  Tests  were  made  by  different  authorities  on  four 
separate  two-cycle  marine  engines  of  standard  type, 
after  being  erected  in  the  works  and  before  installing 
in  the  vessels  for  which  they  were  built,  the  power  being 
absorbed  in  each  case  by  a  brake  of  the  Heenan  &  Froude 
type.  In  the  four  engines  tested  it  was  found  that  the 
fuel  consumption  per  B.H.P.  hour  was  respectively  211 
grams.,  210  grams.,  201*6  grams,  and  196  grams.,  or  an  aver- 
age of  204"5  grams,  or  say  "45  lb.  per  B.H.P.  hour,  which  is 
very  much  the  same  as  for  the  usual  four-cycle  motor.  All 
the  engines  were  of  the  standard  four-cylinder  type,  with 
two  manoeuvring  cylinders  in  line.  An  illustration  of  a  260 
H.P.  engine  is  shown  in  Fig.  122. 

For  larger  marine  Diesel  motors,  that  is  to  say  any- 
thing over  about  500  B.H.P.,  a  different  type  of  engine 
is  built  by  the  same  firm,  although  many  of  the  essential 


236  DIESEL  ENGINES  FOR  LAND  AND  MARINE  WORK 

details  are  embodied  in  the  larger  engine.  A  somewhat 
similar  design,  which  has,  however,  modifications  of  their 
own,  is  built  by  Messrs.  Swan,  Hunter  &  Wigham  Richardson 
in  this  country. 

As  before,  the  motor  is  of  the  two-cycle  single-acting 
type,  but  the  manoeuvring  cylinders  arranged  in  line  with 
the  working  cylinders  are  abolished,  and  replaced  by 
combined  scavenging  pumps  and  mancBuvring  cylinders 
below  the  actual  working  cylinders.  There  is  thus  one 
scavenge  pump  for  each  cylinder,  but  the  arrangement  is 
not  exactly  that  adopted  in  many  other  cases  and  known 
as  the  stepped  piston  design,  since  the  pistons  of  the  w^orking 
cylinders  and  the  air  pump  are  quite  separate  and  the  air 
is  compressed  by  the  scavenge  piston  on  its  downward  and 
not  on  its  upward  stroke.  The  engine  is,  in  many  ways, 
an  extremely  simple  one.  Unlike  practically  every  other 
type,  the  cylinder  and  liner  are  cast  in  one  piece,  the  cylinder 
for  the  scavenge  pump  being  quite  separate.  Port  scaveng- 
ing is  employed  as  in  the  smaller  motors,  and  as  there  is  no 
auxiliary  valve  for  the  admission  of  scavenging  air,  the 
piston  is  shaped  in  order  to  deflect  the  air  upwards  and 
downwards  so  that  good  scavenging  may  be  obtained.  The 
advantage  of  port  scavenging  is  shown  in  the  construction 
of  the  cylinder  cover,  which  contains  only  one  valve,  this 
being  the  ordinary  fuel  inlet  valve  in  the  centre  of  the  cover. 
This  valve  is  of  the  same  type  as  that  described  for  the 
smaller  Polar  engines. 

The  motor  is  practically  of  the  open  type,  and  naturally 
owing  to  the  arrangement  of  scavenge  pumps,  there  is  an 
external  crosshead  and  connecting  rod.  The  cylinders 
are  supported  at  the  back  by  means  of  a  cast-iron  framing 
carrying  also  the  guides  for  the  crossheads,  and  at  the  front 
by  cast-steel  columns,  as  with  some  other  motors,  notably 
the  Sulzer  type  and  also  the  Werkspoor  engine. 

The  important  feature  of  using  the  scavenging  cylinders 
for  starting  purposes  is  retained  in  this  motor  with  the 
result  that  not  only  is  the  simplest  possible  design  of  cover 
obtained,  but  also  the  undesirable  admission  of  cool  air 


CONSTRUCTION   OF  DIESEL  MARINE  ENGINE    237 

into  the  heated  combustion  chamber  during  manoeuvring 
is  avoided.  The  method  involves  a  certain  complication 
in  connexion  with  the  valves  for  the  scavenge    cylinder, 


Fig.  1 17.— Xear  View  of  Cam  Sliaft  of  800  H.P.  Polar  Diesel  :\Iarine  Engine. 


but  otherwise  has  much  to  commend  it.  The  arrangement, 
however,  can  be  reduced  to  comparative  simplicity  in 
operation,  since  when  starting  up  there  is  a  two-way  valve 


238  DIESEL  ENGINES  FOR  LAND  AND  MARINE  WORK 

which  shuts  ojff  the  admission  of  atmospheric  air  into  the 
scavenge  pump,  and  allows  compressed  air  at  a  pressure  of 
about  75  lb.  per  sq.  inch  to  enter  the  scavenging  cylinder 
beneath  the  piston,  and  start  up  the  engine.  The  admission 
and  discharge  valves  on  the  scavenge  pumps  are  mechanic- 
ally operated  by  means  of  eccentric  rods  from  a  horizontal 
spindle  driven  off  the  crank  shaft.  Although  the  pressure 
of  the  starting  air  in  the  scavenge  pump  only  needs  to  be 
75  lb.  per  sq.  inch  it  is  supplied  from  res&rvoirs  at  150  lb. 
per  sq.  inch  to  a  reducing  valve  to  bring  it  down  to  the 
desired  figure. 

For  the  operation  of  the  fuel  valve  in  the  cylinder  cover 
there  is  one  lever  for  each  cylinder  and  two  cams  are  arranged 
on  the  cam  shaft,  one  for  ahead  and  one  for  astern  running. 
An  interesting  and  useful  feature,  however,  lies  in  the  fact 
that  the  two  cams  are  tapered  away,  so  that  the  roller  of 
the  fuel  valve  lever  need  not  be  lifted  when  reversing  as  is 
usually  the  case,  when  ordinary  flat  cams  are  adopted. 
There  is  also  a  half-speed  cam  for  slow  running.  With 
this  engine  the  whole  cam  shaft  is  not  moved  longitudinally, 
as  is  common,  but  only  a  sleeve  carrying  the  two  cams  for 
each  cylinder,  this  movement  being  effected  by  means  of  a 
lever  from  the  starting  platform.  Following  a  practice 
which  is  now  becoming  more  and  more  usual  for  marine 
engines  one  fuel  pump  is  provided  for  each  cylinder,  but 
instead  of  bunching  all  the  pumps  together,  as  is  frequently 
done,  each  one  is  arranged  in  front  of  its  cylinder  and  is 
driven  off  the  cam  shaft  by  means  of  an  eccentric,  the 
pump  itself  being  only  slightly  below  the  level  of  the  shaft. 
For  the  control  of  the  speed  of  the  engine  the  usual  method 
of  operating  upon  the  suction  valve  of  the  fuel  pump  is 
adopted,  and  in  order  to  carry  this  out  there  is  a  long  spindle 
in  front  of  the  engine,  attached  to  levers  which,  when  the 
spindle  is  rotated,  alter  the  stroke  of  the  suction  valve  of 
the  pump,  and  thus  vary  the  speed  of  the  engine.  The 
movement  is  carried  out  by  means  of  a  control  lever  on  the 
starting  platform. 

With  the  motors  of  this  type  which  have   hitherto  been 


tc 

c 


>. 

o 


239 


240    DIESEL  ENGINES  FOR  LAND  AND  MARINE  WORK 

built,  two  separate  two-stage  compressors  have  been 
adopted,  driven  by  means  of  levers  from  the  crossheads 
of  the  two  central  cylinders.  Probably  in  larger  motors 
compressors  of  the  three-stage  type  will  be  employed,  and 
this  has  in  fact  been  done  in  the  Neptune  engine  of 
Messrs.  Swan,  Hunter  &  Wigham  Richardson. 

In  reversing,  apart  from  altering  the  timing  of  the 
fuel  inlet  valve  it  is  necessary  to  operate  the  scavenge 
pump  inlet  and  discharge  valves  at  180°  after  the  ordinary 
timing  for  ahead  running.  This  is  accomplished  in  a  com- 
paratively simple  manner  by  converting  the  inlet  valves 
into  delivery  valves,  and  vice-versa.  The  cylinders  are 
worked  in  pairs  and  it  is  arranged  that  the  two  inlet  valves 
for  two  adjacent  cylinders  are  one  above  the  other,  whilst 
there  is  also  a  delivery  valve  above  another  delivery  valve 
for  the  two  cylinders.  Above  the  casing  which  contains 
the  two  inlet  and  two  delivery  valves  is  what  may  be  termed 
a  distribution  box  in  which  is  a  valve  that  can  be  moved 
to  the  right  or  left.  On  moving  it  to  the  extreme  right  the 
deliver}'  valves  become  the  inlet  valves  for  the  scavenge 
pump  and  the  inlet  valves  are  changed  to  the  delivery  valves, 
which  corresponds  to  the  operation  necessary  for  the  valves 
when  running  in  the  opposite  direction. 

For  the  general  control  and  working  of  the  engine  there 
is  one  main  hand- wheel  which  carries  out  all  the  operations 
necessary  for  reversing,  and  a  lever  which  serves  the  purpose 
of  admitting  starting  air  to  the  scavenging  cylinders  for 
starting  up.  The  hand-wheel  moves  the  cam  blocks  longi- 
tudinally so  as  to  bring  the  ahead  or  astern  cam  under  the 
valve  lever  roller  as  required,  whilst  there  is  also  an  inter- 
mediate position  which  corresponds  to  the  stop  position  on 
the  hand- wheel.  A  half -speed  cam  is  moreover  provided 
which  is  brought  underneath  the  lever  roller  when  it  is 
required  to  run  at  slow  speed  for  some  time. 

In  turning  this  hand-wheel  the  distributing  valves  for  the 
admission  of  air  to  the  scavenging  pump  are  also  operated 
at  the  same  time,  but  the  engine  only  starts  up  when  the 
main  starting  lever  on  the  control  platform  is  actuated  so 


FiCi.    12(1.— 050  B.H.P.  Neptuno  Polar  Marine  Engine,  built  by  Messrs. 


CONSTRUCTION   OF  DIESEL  MARINE  ENGINE    241 

as  to  admit  compressed  air  at  75  lb.  per  sq.  inch,  first  to 
two  manceiivring  cylinders,  then  to  four,  and  finally  to  six. 
It  may  incidentally  be  mentioned  that  if  the  engine  is  warm 


it  is  not  usually  necessary  to  carry  the  operation  beyond 
two  cylinders. 

For  controlling  the  speed  of  the  engine  in  the  ordinary 
course  of  running  there  is  a  ratchet  wheel  operated  from 
the  starting  platform  which  controls  the  suction  valves  of 

B 


CONSTRUCTION   OF  DIESEL  MARINE   ENGINE    243 

the  various  fuel  pumps,  the  action  being  very  much  the 
same  as  is  utiHzed  in  the  land  engines.  A  governor  is  fitted 
which  also  varies  the  stroke  of  all  the  suction  valves  of  the 


fuel  pumps  at  the  same  time,  but  this  motion  is  not  con- 
nected at  all  with  the  throttle  control  on  the  starting 
platform. 


244    DIESEL  ENGINES  FOR  LAND  AND  MARINE  WORK 

All  the  cylinders  are  provided  with  horizontal  relief  valves 
which  may  be  operated  from  the  starting  platform  by  means 
of  a  lever  if  necessary.  It  is  not  usually  essential  for  these 
relief  valves  to  be  opened,  but  if  it  is  found  that  the  motor 
is  difficult  to  start,  which  may  be  accounted  for  by  com- 
pressed air  acting  upon  the  bottom  of  the  scavenge  pump 
pistons  when  the  engine  is  endeavouring  to  fire,  then  the 
relief  valve  may  be  opened,  and  at  the  same  time  compressed 
air  is  automatically  cut  off  from  the  injection  valves. 

Fresh  water  is  employed  for  the  piston  cooling,  but  for 
all  other  piu'poses  sea  water  is  used.  The  delivery  into  and 
discharge  from  the  piston  head  is  arranged  by  means  of 
concentric  pipes  within  the  piston  rod  itself,  the  water 
being  taken  to  these  piston  rods  through  the  levers  which 
operate  the  air  injection  pumps  on  the  front  of  the  engine. 

For  employment  on  submarines  a  new  type  of  engine 
working  on  the  four-cycle  principle  is  built  by  the  Polar 
firm  ;  this  is  capable  of  running  at  a  speed  as  high  as  500 
r.p.m.  and  has  been  adopted  owing  to  the  difficulties  of 
scavenging  and  other  troubles  with  high-speed  two-cycle 
engines. 

German  Types. — A  large  number  of  two-cj^cle  single 
acting  engines  of  the  Diesel  type  have  been  constructed  by 
Messrs.  Krupp  of  Kiel,  of  which  several  were  for  the  German 
and  Italian  Navies,  but  recently  four  engines  each  of  1 ,250 
B.H.P.  running  at  14.0  revolutions  per  minute  have  been 
built  for  the  Deutsch-Amerikanische  Petroleumgesellschaft 
for  tank  vessels.  All  engines  of  over  300  H.P.  are  made  on 
the  two-cj^cle  principle,  Mhile  those  below  this  power  are  four 
cycle,  in  each  case  being  directly  reversible  except  for  the 
very  smallest  sizes.  Fig.  123  shows  a  high  speed  two-cycle 
reversible  marine  engine  of  Messrs.  Krupp 's  construction, 
of  1,000  B.H.P. ,  recently  supplied  to  the  German  Admir- 
alty, and  this  is  typical  of  the  general  design  of  the  two- 
cycle  engine.  There  are  six  working  cylinders  divided 
into  two  sections  of  three  each,  with  the  air  compressor  in 
the  centre  and  a  scavenging  air  pump  at  each  end,  the 
peculiar  construction  of  the  suction  chambers  being  well 


I  I 

I  I 

I  ' 

I  I 

I  I 

r-'--L, 


246    DIESEL  ENGINES  FOR  LAND  AND  MARINE  WORK 

seen  in  the  illustration.  Each  scavenging  pump  supplies 
three  of  the  cylinders,  which  thus  form  a  completely  inde- 
pendent set,  so  that  for  low  powers  only  one-half  of  working 
cylinders  need  be  in  operation  and  a  greater  reduction 
in  power  may  thus  be  obtained,  with  corresponding  increase 
in  manoeuvring  facilities.  For  the  engine  exhaust,  ports 
at  the  bottom  of  the  cyhnder  are  employed  as  usual  with 
two-cycle  motors,  and  the  scavenge  air  is  admitted  through 
valves  in  the  cylinder  head.  The  crank  chambers  are 
totally  enclosed,  with  inspection  doors  in  front  of  each 
cylinder  for  examining  the  cranks  and  bearings. 

The  method  of  reversing  in  this  engine  consists  in  the 

employment  of  ahead 
r  1  r  -  and  reverse    cams  on 

the  same  cam  shaft, 
which  is  moved  axially 
during  reversing  so  as 
to  bring  the  ahead  or 
astern  cams  under- 
neath the  valve  levers 
.._  operating  the  valves 
as  required .  The 
valves  which  require 
an    alteration  in    the 

Fig.    124.-Diagram  shovving  action  of        ^-j^^g   ^f  opening  dur- 
Cams  for  Krupp  s  Engine.  .  ^  ® 

ing  reversal  are  the 
fuel  inlet  valve,  the  starting  valve  and  the  scavenge 
valve,  unless  ports  in  the  cylinder  be  employed  instead  of 
the  latter,  which  is  sometimes  the  case.  The  cams  for  the 
fuel  and  scavenge  valves  are  arranged  somewhat  as  shown 
diagrammatically  in  Fig.  124,  there  being  a  flat  space  be- 
tween the  ahead  and  astern  cam  pieces,  this  being  the 
position  of  rest  for  the  roller  of  the  valve  lever  when  the 
engine  is  stopped.  For  the  starting  valve  two  separate  cams 
are  provided,  one  for  ahead  and  one  for  astern,  and  either 
of  these  may  be  put  into  operation  according  to  the  direc- 
tion of  rotation  required.  The  action  of  reversing  may  be 
explained  as  follows.     Assume  the  engine  is  running  ahead, 


-f 


CONSTRUCTION  OF  BTESEL  MARINE  ENGINE    247 

in  which  case  the  rollers  for  the  scavenge  air  and  fuel  inlet 
valves  will  be  in  position  as  at  A  in  Fig.  124,  while  both  the 
rollers  of  the  starting  valve  levers  will  be  raised  well  above 
the  cams  which  operate  them.  To  bring  the  engine  to 
rest  the  whole  of  the  cam  shaft  is  moved  to  the  left,  a  dis- 
tance equal  to  half  the  longitudinal  distance  between  the 
centres  of  the  ahead  and  reverse  cams.  The  rollers  operat- 
ing the  valve  levers  then  rest  on  the  flat  portion  of  the 
cam  sleeve  as  at  B,  Fig.  124,  and  the  valves  are  not  opened 
as  the  cam  shaft  rotates.  This  movement  of  the  cam 
shaft  is  carried  out  by  means  of  the  hand- wheel  seen  in  the 
centre  of  the  engine  in  Fig.  123,  which  causes  the  motion 
through  screw  gearing.  The  scavenge  air  and  fuel  inlet 
valve  levers  being  in  the  stop  position  the  engine  comes  to 
rest,  after  which  the  starting  valve  lever  for  reverse  running 
is  brought  down  on  its  cam  by  means  of  one  of  the  two 
levers  seen  in  the  centre  of  the  engine,  which  give  an  angular 
motion  to  a  shaft  underneath  the  cam  shaft  and  connected 
to  it  by  small  coupling  rods.  The  starting  valves  are 
opened,  the  engine  runs  up  as  an  air  motor,  and  after  two 
or  three  revolutions  the  starting  valve  levers  are  raised  off 
their  cam  by  putting  the  main  controlling  handle  back  to 
mid  position,  and  the  cam  shaft  is  moved  further  to  the 
left  a  distance  equal  to  the  first  until  the  rollers  of  the  valve 
levers  are  in  the  position  C,  Fig.  124,  which  is  the  astern 
running  position.  The  main  starting  lever  controlling 
the  starting  valves  and  the  wheel  controlling  the  position 
of  the  cam  shaft  are  properly  interlocked  so  that  there  may 
be  no  possibility  of  the  fuel  inlet  valve  being  opened  during 
the  starting  period. 

For  their  standard  engine  of  the  slow  speed  type,  suitable 
for  large  cargo  and  similar  vessels,  Messrs.  Krupp  have 
adopted  a  different  design,  and  several  of  this  new  type  have 
already  been  constructed.  The  two-cycle  single  acting 
principle  is  retained,  and  in  some  respects  the  engine  is 
similar  to  that  developed  by  Messrs.  Carels,  as  previously 
described,  being  of  the  open  crosshead  type.  In  all  sizes 
of  motor  which  have  at  present  been  constructed  (ranging 


248    DIESEL  ENGINES  FOR  LAND  AND  MARINE  WORK 


Fig.  125. — Section  through  Cylinder  and  Scavenge  Pump  of  1,250  B.H.P. 

Krupp  Engine. 

from  1,000  B.H.P.  to  2,500  B.H.P.)  six  cylinders  have  been 
employed,    with   two   scavenge  cylinders    arranged  at  the 


CONSTRUCTION   OF  DIKSEL   MARINE  ENGINE    249 

back  of  the  engine,  driven  from  tlie  crossheads  of  the  two 
centre  working  cyHndcrs  through  rocldng  levers. 

The  air  compressors  for  the  supply  of  starting  and  injec- 
tion  air   and   for   manoeuvring    are    separately    driven,    so 


that  the  engine  itself  consists  only  of  the  working  cylinders 
and  the  scavenge  pumps.  Scavenging  is  effected  by  means 
of  valves  in  the  cylinder  cover,  there  being  two  per  cylinder, 
but  it  may  be  mentioned  that  this  is  not  likely  to  be  the 


250    DIESEL  ENGINES  FOR  LAND  AND  MARINE  WORK 

ultimate  design.  As  v^iU  be  noticed  from  Figs.  125  and  126, 
the  scavenge  pumps  are  supported  from  the  engine  frame 
and  raised  above  the  engine-room  floor  level,  thus  differing 
from  the  arrangement  adopted  by  Messrs.  Carels.     A  stuffing 


'So 

c 


box  is  provided  at  the  bottom  of  the  cylinder,  to  prevent 
the  escape  of  exhaust  gas  into  the  engme-room. 

The  cylinders  are  supported  on  an  "A"  shaped  frame 
formed  by  box  columns  fixed  to  the  bed-plate,  and  the 


CONSTRUCTION   OF  DIESEL  MARINE   ENGINE    2ra 

crosshead  guide  surfaces  are  formed  on  the  inside  of  the 
cohimiis  and  are  \\ater  cooled.  The  arrangement  and 
construction  of  the  piston  are  seen  from  the  illustration, 
which  also  indicates  that  the  stroke  is  relatively  long  com- 
pared with  the  bore  of  the  cylinders.  It  may  be  mentioned 
that  the  speeds  of  this  type  of  engines  vary  from  1 00  to  1 60 
r.p.m.,  accoi^ding  to  the  size  and  also  the  speed  of  the  vessel 
in  which  they  are  installed. 

The  arrangements  adopted  for  reversing  follow  much  on 
the  lines  of  those  already  described  for  the  high-speed  two- 
cycle  engine  of  this  firm.  A  single  cam  shaft  is  employed, 
on  which  both  ahead  and  astern  cams  are  mounted,  and 
this  is  moved  longitudinally  to  bring  the  astern  or  ahead 
cams  underneath  the  valve  levers,  according  to  the  direction 
of  rotation  required.  The  movement  is  effected  either  by 
hand  or  by  means  of  a  small  compressed  air  motor,  and 
a  manoeuvring  hand-wheel  is  provided,  which  allows  the 
engine  to  run  up  on  compressed  air,  and  finally  brings  fuel 
on  to  all  the  cylinders  for  full  speed.  Before  moving  the 
cam  shaft  longitudinally,  all  the  valve  levers  are  raised  off 
the  cams,  in  the  usual  manner  adopted  with  two-cycle 
engines  when  this  method  of  reversing  is   employed. 

The  weight  of  this  type  of  engine  is  about  250  lb.  per 
B.H.P.,  and  the  fuel  consumption  is  about  0*44  lb.  per 
B.H.P.,  which  includes  the  operation  of  the  scavenge  pumps 
but  not  the  air  compressors.  Reversing  from  full  speed  ahead 
to  full  speed  astern  is  accomplished  in  about  12  seconds.  An 
illustration  of  the  reversing  mechanism  is  given  in  Fig.  128. 

Diesel  engines  for  marine  work  are  built  at  the  Niirnberg 
Works  of  the  Maschinenfabrik  Augsburg-Niirnberg,  of  the 
two-stroke  cycle  type,  but  are  divided  into  two  classes — 
the  light  and  the  heavy  weight  type,  the  former  being 
chiefly  designed  for  submarines,  gunboats  and  torpedo 
boats,  while  the  latter  are  more  suitable  for  tug  boats  and 
cargo  vessels.  The  weight  of  the  light  type  is  from  about 
30-35  lb.  per  B.H.P.  hour  for  large  engines  up  to  40  lb. 
per  B.H.P.  hour  for  small  engines,  this  being  an  inclusive 
weight.     The  engines  are  commonly  built  of    six  cylinders 


252    DIESEL  ENGINES  FOR  LAND  AND  MARINE  WORK 


without  a  flywheel,  or  four  cylinders  with  a  flywheel,  but 
sometimes  eight  cylinders  are  employed.  The  types  stan- 
dardized for  the  light  weight  engine  are  as  under  : — 

150  H.P.  at  550  revs,  per  min. 
200  „  „  550 
300-500  ,,  ,,500 
600  „  „  450 
900  ,,  „  420 
1,200      „       ,,    400 


The  approximate  dimensions  of  some  of  these    engines 
are  as  under  : — 


Horse  power 

150 

200 

300 

400 

500 

GOO 

ft.    in. 

ft.     in. 

ft.     in. 

ft.     in. 

ft. 

in. 

ft.    in. 

Overall  lengtli  . 

9    101 

11      5| 

12     9| 

14      51 

14 

9i 

15     9 

Overall  width    . 

2     2^ 

2     7| 

2   Hi 

3     41 

3 

7 

3  Hi 

Height      required      for 

dismantling   . 

4     41 

4   111 

5     7 

6     3 

G 

6| 

6  10| 

Depth   required   below 

centre  of  crank  shaft 

1      li 

1      21 

1      5 

1     53- 

1 

7 

1  n 

The  usual  speeds  of  the  heavy  weight  engines  are    as 
follows  : — 

150-200  B.H.P.  at  300-400  revs,  per  min. 
300-330       ,,  ,,   300-330 


450-550 

„   225-275 

600-750 

,,   225-275 

900       ,, 

260 

1,200       „ 

215 

The  heavy  engines  are  cheaper  as  the  framework  and 
bed-plate  are  of  cast  iron,  whilst  with  the  lighter  type 
manganese  bronze  is  usually  employed.  The  speed  is 
also  less  and  the  fuel  consumption  is  lower  with  the  heavy 
type  than  with  the  light  weight  motor. 


[To  face  page  252. 


Fla.    1 28.— Rovereiiig  Meclionism  of  Krupp  Engi 


ITo/acr  pant  252. 


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ISiM^ 

San 

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«    ■ 

%    Mr 

k^""-s!_ 

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^^ 

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K]i:.    IJ'.l— l.jr.u   llHl'.    Krupp    IVu  Cy.l.-   Mil 


CONSTRUCTION   OF  DIESEL   MARINE   ENGINE    253 


\X 


Large  engines  are  provided  with  two  two-stage  com- 
pressors for  the  injection  and  starting  air,  while  smaller 
motors  have  but  one  compressor,  the  usual  arrangement 
being  to  have  it  at  one  end  of  the  engine.  The  scavenge 
pumps  are  below  the 
working  cylinders,  one 
for  each  cylinder,  the 
pistons  being  stepped 
and  enlarged  at  the 
bottom  to  form  the 
piston  of  the  scavenge 
pump,  while  it  also  acts 
as  the  crosshead  for  the 
piston  rod.  The  admis- 
sion   of     the    scavenge 


air  takes  place  through    <^-^p^ 
valves   in    the  cylinder 
head. 

The  arrangement  of 
the  working  cylinder 
and  the  scavenge  cylin- 
der is  shown  in  trans- 
vere  section  in  Fig.  130, 
the  effective  sectional 
area  of  the  scavenge 
cylinder  being  the  dif- 
ference between  that  of 
the  working  cylinder 
and  the  scavenge  cylin- 
der itself.  A  s  t  h  e 
volume  of  scavenge  air 
required  is  usually 
taken  as  1'2  to  I'S 
times  the  volume  swept 
through  by  the  piston 
of  the  working  cylinder, 

the       diameter      of      the     ^^^-    130.— Diagrainniatic    Representation 

of  Niirnberg  Two-Cycle  Marine  Engine, 
scavenge  piston  is  from  showing  Scavenge 'Arrangements. 


254    DIESEL  ENGINES  FOR  LAND  AND  MARINE  WORK 

r4  to  r6  times  the  diameter  of  the   working   piston,   the 
latter  figure  being  for  high  speed  engines . 

In  Fig.  130,  which  is  purely  diagrammatic,  A  represents 
the  working  cylinder,  B  the  scavenge  cylinder,  G  the  fuel 
admission  valve,  D  the  starting  valve,  and  E  the  scavenge 
air  admission  valve.  F  is  the  outlet  valve  in  the  scavenge 
cylinder,  through  which  the  scavenge  air  passes,  after  being 
compressed  to  a  few  pounds  above  atmosphere,  into  the 
receiver  G,  whence  it  enters  the  working  cylinder  through  E, 
when  this  latter  valve  opens.  H  is  the  admission  valve 
of  the  scavenge  cylinder  through  which  air  is  drawn  into 
the  scavenge  cylinder,  during  the  suction  or  downward 
stroke  of  the  piston.  In  the  position  shown  in  the  figure, 
the  working  piston  is  just  finishing  the  compression  or 
upward  stroke  in  which  the  air  is  compressed  to  the  pres- 
sure required  for  combustion  of  the  fuel.  When  the  crank 
has  nearly  reached  the  top  dead  centre  J,  the  fuel  admission 
valve  opens  and  combustion  takes  place,  and  the  piston 
starts  on  its  downward  or  working  stroke,  while  //  is  also 
opened  and  air  is  drawn  into  the  scavenge  cylinder.  Just 
before  the  crank  reaches  the  bottom  dead  centre  K,  the 
YStlveE  opens,  scavenge  air  enters  from  the  receiver  G,  and 
expels  the  exhaust  gases  in  the  worldng  cylinder  through 
the  ports  L  which  are  then  uncovered  by  the  piston,  F  being 
closed  and  H  open  during  the  whole  of  this  stroke.  After 
the  crank  passes  the  dead  centre,  F  opens,  and  H  closes, 
while  the  valve  remains  open  till  just  after  the  exhaust 
ports  L  are  closed  by  the  piston,  when  it  closes,  and  during 
the  remainder  of  the  upward  stroke  F  is  kept  open  and 
the  receiver  G  is  charged  with  scavenge  air  from  the 
scavenge  cylinder,  while  the  air  in  the  working  cylinder  is 
compressed.  When  starting  up  the  engine  by  the  admis- 
sion of  air  through  the  starting  valve  D  in  the  usual  way, 
this  air  is  effectively  discharged  through  the  exhaust  ports 
in  the  cylinder  by  admitting  scavenge  air  through  the 
scavenge  valve  E  so  long  as  these  ports  remain  uncovered 
by  the  piston. 

The  working  pistons  are  cooled  with  oil  and  the  cylinder 


CONSTRUCTION   OF  DIESEL  MARINE   ENGINE    255 

jackets  have  removable  covers  which  are  useful  for  clean- 
ing the  jackets,  rendered  necessary  by  the  employment  of 
salt  water  for  cooUng  purposes.  Forced  lubrication  is 
adopted  and  the  oil  passes  through  a  cooler  and  is  enabled 
to  be  used  over  again. 


Fig.   131. — Diagram  illustrating  Metliod  of  Reversing  Niirnbcrg  Engine. 


As  is  necessary  in  all  two-cycle  engines  in  which  scavenge 
valves  and  not  ports  are  employed,  in  reversing,  the  times 
of  opening  of  three  valves  have  to  be  altered-^namely,  the 
starting  valve,  the  fuel  valve,  and  the  air  inlet  and  scavenge 
valve.  This  is  accomplished  in  the  case  of  the  two  latter 
by  turning  the  cam  sliaft  itself  through  a  certain  angle 


256    DIESEL  ENGINES  FOR  LAND  AND  MARINE  WORK 

(about  30°  in  the  case  of  the  Niirnberg  engine)  so  that  but 
one  cam  is  needed  for  each  scavenge  valve  and  each  fuel 
valve,  both  for  ahead  and  reverse  running.  In  order  that 
the  scavenge  and  fuel  valves  may  be  set  in  the  reverse 
position  together,  by  the  same  movement  of  the  cam  shaft, 
it  is  necessary  that  the  angles  of  opening  and  preadmission 
of  these  valves  should  be  in  a  certain  definite  ratio.  This 
can  be  better  explained  by  a  reference  to  Fig.  131,  which 
represents  a  crank  diagram  for  the  engine,  A  being  the  top 
dead  centre  and  E  the  bottom.  The  question  to  be  solved 
is,  to  so  adjust  the  angle  of  opening  (referred  to  the  rotation 
of  the  crank  shaft)  of  the  scavenge  and  fuel  inlet  valves, 
that  the  cams  operating  their  valve  levers  will  have  an  axis 
of  symmetry,  with  the  result  that  by  the  same  alteration 
of  angle  of  the  cam  shaft,  both  the  fuel  valve  and  the  sca- 
venge valve  are  set  for  reverse  running.  In  Fig.  131  B  is, 
the  point  of  admission  of  the  fuel,  the  angle  of  preadmis- 
sion being  d.  The  valve  closes  at  D  so  that  the  total  angle 
of  opening  is  a. 

K  represents  the  point  of  uncovering  of  the  exhaust  ports 
and  L  of  their  closing,  but  these  do  not  enter  into  the  ques- 
tion since,  of  course,  no  alteration  is  necessary  in  reversing. 
At  i^  the  scavenge  valve  opens,  the  closing  point  being  H , 
and  the  full  angle  of  opening  h.  The  angle  of  preadmission 
for  the  scavenge  air  is  e. 

The  respective  total  angles  of  opening  of  the  fuel  valve 
{a)  and  the  scavenge  valve  (h)  are  so  adjusted  that 

a   =  c  +  2fZ 
and  6   =  c  +   2e 

or  in  other  words  the  angle  of  opening  in  both  cases  is  twice 
the  angle  of  preadmission,  plus  a  constant  angle  c.  In  the 
diagram  if  the  lines  0  0^  and  0  O2  be  drawn  bisecting  the 
angles  a  and  h  it  is  easy  to  show  that  the  angle  gr  is  180°  and 
therefore  the  line  Oj  O2  is  the  axis  of  symmetry  for  the  fuel 
valve  and  scavenge  valve  cams. 

To  explain  the  action  of  reversing  consider  the  engine  to 
be  running  in  the  ahead  direction  as  indicated  by  the  arrow 


CONSTRUCTION  OF  DIESEL  MARINE  ENGINE    257 

S,  A  and  B  are  the  top  and  bottom  dead  centres  of  the  crank, 
and  the  angles  BOA  or  d  and  F  O  E  or  e  are  the  respective 
angles  of  preadmission  for  the  fuel  and  the  scavenge  valves. 

When  the  engine  is  started  up  in  the  reverse  direction, 
which  is  accomplished  by  means  of  compressed  air,  as  is 
explained  later,  the  crank  is  running  in  the  direction  indi- 
cated by  the  arrow  R,  and  all  that  is  necessary  to  set  the 
cams  in  the  correct  position  is  to  move  the  cam  shaft  through 
an  angle  equal  to  c  so  that  in  the  diagram  C  and  G  become 
the  respective  top  and  bottom  dead  points.  The  angles  of 
preadmission  are  then  D  0  C  or  d  and  G  0  H  or  e  for  the  fuel 
and  scavenge  valves  respectively,  which  are  exactly  the 
same  as  when  running  in  the  ahead  direction.  The  cams 
are  therefore  in  the  correct  position  for  reverse  running 
and  the  operation  is  exactly  the  same  as  for  the  ahead 
rotation. 

For  the  starting  valve,  if  its  cam  were  turned  through  an 
angle  of  only  30°,  the  opening  of  the  valve  would  be  a  small 
period,  since  it  would  also  have  to  be  30°  plus  twice  the  angle 
of  preadmission,  which  is  small.  Hence  an  insufficient 
starting  torque  would  be  produced  and  other  means  have  to 
be  adopted.  The  arrangement  used  is  to  have  two  cams  for 
each  starting  valve  (of  which  there  is  of  course  one  for  each 
cylinder),  one  cam  for  ahead  and  the  other  for  reverse 
running.  These  cams  actuate  a  small  valve  which  regulates 
the  admission  of  compressed  air  to  the  starting  valve,  and 
according  to  which  cam  comes  into  operation  the  direction 
of  rotation  of  the  engine  at  starting  is  controlled. 

A  single  lever  controls  the  whole  operation  of  reversing. 
In  the  stop  position  it  is  in  the  middle,  while  for  ahead  run- 
ning it  is  moved  to  the  right,  and  for  astern  to  the  left,  its 
movement  allowing  the  injection  air  to  pass  to  the  ahead  or 
astern  air  valve  previously  mentioned.  When  the  engine 
starts  up  in  the  required  direction  it  automatically  sets  the 
cams  for  the  fuel  and  scavenge  valves  in  their  right  position, 
namely,  in  reverse  running  it  turns  the  cam  shaft  through 
an  angle  of  30°.  This  is  carried  out  by  driving  the  vertical 
intermediate  shaft  operating  the  horizontal  cam  shaft  by 

s 


258    DIESEL  ENGINES  FOR  LAND  AND  MARINE  WORK 

means  of  a  claw  coupling,  the  teeth  or  claws  of  which  have 
a  clearance  angle  of  30°  instead  of  the  faces  bearing  against 
each  other  as  is  usual  with  these  couplings.  When  the 
engine  is  running  in  the  ahead  direction  the  front  faces  of  the 
claws  of  the  half  of  the  coupling  keyed  to  the  crank  shaft 
bear  hard  against  the  hack  faces  of  the  half  of  the  coupling 
attached  to  the  vertical  shaft.  On  reversing  the  engine, 
by  movement  of  the  controlling  handle  and  starting  up  on 
compressed  air,  the  part  of  the  coupling  on  the  crank  shaft 
runs  free  for  an  angle  of  30°  when  the  hack  faces  of  its  teeth 
come  against  the  front  faces  of  claws  of  the  half  of  the  coup- 
ling on  the  vertical  shaft.  The  coupling  then  drives  this 
shaft,  and  hence  the  cam  shaft  in  this  position,  the  result 
being  that  the  cam  shaft  is  automatically  turned  through  an 
angle  of  30°  relative  to  the  crank  shaft,  and  the  cams  are 
thus  in  the  required  position  for  astern  running.  In  order 
that  there  may  be  no  play  in  the  coupling  when  the  engine 
is  running,  strong  springs  keep  the  two  halves  of  the 
coupling  together. 

The  engines  are  of  six  or  eight  cylinders,  the  cranks 
being  set  at  120°  or  90°  in  the  two  cases  respectively.  The 
general  arrangement  of  this  type  of  motor  can  be  seen  from 
Fig.  132,  which  represents  a  longitudinal  section  of  the 
engine.  The  air  pumps  are  fitted  on  the  forward  end  of  the 
engine,  these  consisting  of  two  two-stage  compressors, 
and  the  design  may  be  compared  with  the  submarine 
motors  of  the  Krupp  and  similar  designs.  The  cranks 
for  these  two  pumps  are  set  at  180°,  which  aids  con- 
siderably in  the  smooth  running  of  the  machine.  The  cylin- 
ders may  be  of  cast  steel  or  cast  iron,  and  the  pistons  are  oil 
cooled — a  point  of  more  than  ordinary  interest.  The  speed 
can  be  reduced  to  20  per  cent,  of  the  normal  full  speed  of 
the  engine. 

The  circulating  pumps  for  the  cooling  water  are  driven  off 
the  engine,  and  the  water  passed  through  the  air-pump 
cylinder  jackets,  the  bearings,  the  oil  cooler,  cylinders, 
exhaust  valves,  the  exhaust  pipe,  and  thence  overboard. 
Forced  lubrication  is  adopted  throughout,  the  oil  pressure 


Fio.   132. — Sectional   Illustrations  of  Xiirnborg  Marine  En. 


[To  face  ]>aji  258. 


Fig.   133. — End  View  of  Niirnberg  Marine  Engine. 
259 


260    DIESEL  ENGINES  FOR  LAND  AND  MARINE  WORK 

being  from  30  to  50  lb.  per  sq.  in.  It  passes  through  the 
hollow  crank  shaft  and  the  gudgeon  pins,  and  is  then  utilized 
for  piston  cooling. 

The  consumption  in  these  motors  is  relatively  low,  being 
in  the  neighbourhood  of  0"44  lb.  per  B.H.P.  hour,  which  may 
be  taken  as  a  very  fair  figure  for  this  type  of  engine. 

An  illustration  of  one  of  the  heavy  weight  type  engines 
(which  it  must  be  remembered  is  purely  a  relative  term)  is 
given  in  Figs.  133  and  135.  A  motor  of  this  type  of  900  H.P., 
running  at  250  revolutions  per  minute,  has  six  cylinders, 
each  of  diameter  360  mm.,  the  stroke  being  600  mm.  The 
two-stage  compressors  are  direct  driven  from  the  crank  shaft 
and  have  cylinder  diameters  of  200  and  100  mm.  respec- 
tively, with  a  stroke  of  450  mm.  The  pistons  are  cooled 
with  lubricating  oil,  and  the  cylinders,  in  the  ordinary 
manner,  with  water.  The  oil  pumps  and  cooling  water 
pumps  are  fitted  to  the  front  of  the  main  engine.  The 
weight  of  this  engine,  calculated  on  its  rated  power  of  900 
B.H.P. ,  is  about  120  lb.  per  B.H.P,,  and  as  an  indication 
of  the  overloads  which  Diesel  engines  will  take,  it  may  be 
mentioned  that  the  engine  can  be  speeded  up  to  300 
revolutions  per  minute  and  deliver  1,100  B.H.P.  continuously. 
The  minimum  speed  at  which  the  motor  runs  is  50  revolutions 
per  minute,  i.e.  20  per  cent,  of  full  speed,  which  is  quite 
sufficient  for  all  purposes  of  manoeuvring,  and  this  is  accom- 
plished by  cutting  out  three  cylinders  entirely.  The 
fuel  consumption  is  about  0*47  lb.  per  B.H.P.  hour,  and 
in  this  respect  is  slightly  inferior  to  the  best  open  type  slow- 
speed  marine  Diesel  engines,  which  usually  have  a  consump- 
tion of  0-42  to  0-44  lb.  per  B.H.P.  hour. 

For  larger  powers  an  intermediate  type  of  motor  is  con- 
structed by  the  M.A.N.,  resembUng  in  many  ways  those  of 
the  Krupp  and  Carels  designs.  It  is  an  open  type  engine 
for  powers  of  1,000  to  2,000  H.P.,  and  is  naturally  much 
heavier  than  the  relatively  light  motors  already  described, 
its  weight  being  between  180  and  220  lb.  per  B.H.P.,  accord- 
ing to  the  size  and  circumstances,  whilst  the  speed  varies 
between  100  and  150  revolutions  per  minute. 


CONSTIirCTrON   OF   r)TESP:L  MAPxTNE   ENGINE       261 


The  scavenge  pumps  are  situated  at  the  side  of  the  main 
engine  and  driven  by  rocking  levers  off  the  crossheads,  the 
stepped  piston  arrangement  on  this  type  naturally  being 


262    DIESEL  ENGINES  FOR  LAND  AND  MARINE  WORK 

abandoned.  The  compressors  are  driven  direct  off  the  crank 
shaft  at  the  forward  end  of  the  engine  m  the  usual  manner. 

Engines  of  the  two-cycle  double  acting  type  are  now  being 
built  by  the  Maschinenfabrik  Augsburg-Niirnberg,  and 
apart  from  the  principle  of  action  there  are  various  points 
in  the  construction  differing  from  the  single  acting  type. 
The  engines  have  three  working  cylinders,  and  the  scavenge 
cylinders  are  separate,  though  there  still  remains  one  for  each 
working  cylinder.  These  scavenge  pumps  may  either  be 
mounted  in  line  with  the  main  cylinders  and  driven  direct 
off  the  crank  shaft,  or  arranged  in  front  of  the  engine,  and 
driven  by  levers  from  the  crossheads.  Fuel  and  starting 
valves  are  provided  at  both  ends  of  the  cylinders,  and  are 
worked  from  separate  cam  shafts  in  front  of  the  engines,  the 
means  employed  for  reversing  being  similar  to  that  already 
described  for  the  single  acting  engine,  but  the  reversing  gear 
operates  both  cam  shafts.  As  previously  mentioned  in  dis- 
cussing this  type  of  engine,  two  fuel  valves  are  fitted  in  the 
bottom  of  each  cylinder  on  account  of  the  stuffing  box,  which 
is  of  the  same  type  as  used  for  double  acting  gas  engines. 
For  running  at  low  speeds  the  fuel  valves  at  the  bottom 
may  be  put  out  of  operation,  when  the  engine  works  single 
acting. 

The  scavenge  air  is  usually  arranged  to  enter  at  both  sides, 
and  there  are  exhaust  pipes  both  at  the  back  and  the  front 
of  the  engine. 

The  following  are  the  standard  sizes  to  be  adopted ; 
engines  of  1,000  H.P.  are  already  running,  while  two  of 
1,500  H.P.  each  have  also  been  built: — 


Output  B.H.P. 

Pvovs.  por  minuto. 

750-1,100 

100-140 

1,100-1,900 

100-140 

1,700-2,700 

100-140 

2,400-3,800 

100-140 

3,100-4,900 

100-140 

4,100-5,200 

100-120 

[To  face  page,  262. 


M 


aikors  Marine  Diesel  Engine. 

[To  face  page  262. 


Fig.    130.— S5(1  B.H.P.  Wps.-i--.Juiikci«  jMoi  in.'  Dipscl  Engiiii?. 

[To  face  page  262. 


M 


Fn;.    l:!7.-siO  B.H.r.  W,«.i--Juiik.ra  Marine  Enjjiuo.  [To /uic  j/fijc  2li2. 


CONSTRrCTTON   OF  BTESEL   MARINE   ENGINE    2G3 

One  of  the  most  distinct  departures  from  standard  practice 
in  the  design  of  Diesel  engines  is  that  of  Professor  Junkers, 
although  in  his  arrangement  he  has  brought  some  well- 
known  applications  from  gas-engine  construction  into  force. 

Two  pistons  are  employed  in  each  cylinder,  moving  out- 
ward from,  and  inward  to,  the  centre  of  the  cylinder  at  the 
same  time.  The  bottom  piston  drives  the  crank  shaft  in  the 
usual  manner  through  a  connecting  rod,  whilst  the  upper 
one  is  attached  by  means  of  a  beam  lever  to  two  long  side 
rods  outside  the  cylinder  coupled  to  connecting  rods  driving 
cranks  on  the  crank  shaft. 

Both  top  and  bottom  of  the  cyHnder  are  open  and  the  only 
valves  required  are  one  or  two  fuel  inlet  valves  in  the  centre 
of  the  cylinder,  these  being  of  course  horizontal,  and  injecting 
oil  between  the  two  pistons  as  they  reach  the  centre  of  the 
cylinder.  With  the  Junkers  engine  scavenging  can  be  very 
effectively  carried  out,  the  arrangement  of  ports  being  that 
those  for  scavenging  are  disposed  right  at  the  bottom  of  the 
cyUnder  whilst  the  exhaust  ports  are  at  the  top,  and  these 
can  be  of  more  liberal  dimensions  than  usual  owing  to  the 
greater  available  area.  As  the  pistons  reach  the  outer  end 
of  their  stroke,  air  enters  the  scavenge  ports  and  sweeps 
right  through  the  cylinder  upwards,  passing  out  through  the 
exhaust  ports  at  the  top.  There  is  little  doubt  that  this 
method  is  a  very  satisfactory  one,  and  particularly  so  from 
the  fact  that  the  scavenging  air  is  quite  cold,  which  is  not 
the  case  with  most  other  types  of  scavenging  gear.  Usually 
two  double-acting  scavenge  pumps  are  mounted  on  the  end 
of  the  engine  driven  direct  off  the  crank  shaft,  and  these  are 
provided  with  automatic  valves.  These  pumps  can,  if  de- 
sired, owing  to  exigencies  of  space,  be  arranged  at  right 
angles  to  the  engine  driven  off  the  crossheads,  as  in  the  case 
of  the  Carels  and  other  motors. 

In  the  usual  design  a  fuel  pump  is  provided  for  each  cylin- 
der, and  the  governor  controls  the  admission  of  fuel  by  means 
of  the  suction  valve  of  the  pump.  The  method  of  reversing 
is  relatively  simple,  owing  to  the  small  number  of  valves, 
and  consists  in  altering  the  angular  position  of  the  cam 


264    DIESEL  ENGINES  FOR  LAND  AND  MARINE  WORK 

shaft  in  respect  to  the  crank  shaft.  Starting  is  effected  by 
compressed  air,  and  the  compressor  is  usually  separately 
driven. 

These  motors  have  been  built  in  as  small  sizes  as  100 
B.H.P.  and  up  to  1,200  B.H.P. 

British  Types. — There  are  two  interesting  designs  of 
marine  Diesel  engines  which  have  been  developed  in  this 
country,  and  which,  although  they  are  not  likely  to  be  pro- 
duced commercially  on  an  extensive  scale,  offer  some  points 
of  interest,  especially  as  they  show  the  trend  of  thought  in 
Diesel  engine  design  of  those  who  take  up  the  question 
independently. 

The  Tanner-Diesel  motor,  illustrated  in  Fig.  138,  is  the  one 
which  perhaps  shows  most  marked  deviation  from  ordinary 
practice,  and  an  experimental  engine  of  this  type  was  built 
by  Messrs.  Workman,  Clark  &  Co.  It  is  of  the  two-cycle, 
single-acting  design,  and  in  view  of  the  desire  to  render  it 
particularly  suitable  for  large  powers,  certain  peculiar  points 
have  been  incorporated  which  render  it  of  special  interest. 

As  far  as  possible,  valves  are  dispensed  with,  and  at  the 
present  stage  of  Diesel  engine  development,  there  seems 
no  doubt  that  this  will  find  general  favour.  The  scavenge 
ports  at  the  bottom  of  the  cylinder  do  not  call  for  any  special 
comment,  no  auxiliary  valve  being  employed,  as  in  the 
Sulzer  type.  The  ports  occupy  one-half  of  the  circum- 
ference, the  other  half  being  utilized  for  the  exhaust  ports. 
Instead  of  having  a  scavenge  pump  driven  separately  or 
directly  off  the  crank  shaft,  a  turbo-blower  is  employed, 
the  advantage  of  which  is  its  comparatively  high  efficiency 
and  the  ease  mth  which  the  supply  of  air  may  be  regulated. 
It  would  seem  that  this  arrangement  possesses  some  advan- 
tages in  the  case  of  large  units,  although  for  small  powers 
it  is  somewhat  of  a  detriment  to  add  to  the  number  of 
auxiliaries  to  which  attention  has  to  be  given.  The  pressure 
of  the  scavenging  air  is  about  2 J  lb.  per  sq.  in.,  which  is 
rather  lower  than  the  ordinary. 

In  this  design,  the  aim  has  apparently  been  to  render 
it  suitable  for  a  double-acting  engine  with  as  little  alteration 


i 


[To  face  page  2G4. 


Fici.    13S.— TaimcrDicsol   Moriiie  Engine — Two-Cjclp  SinglcAcling  Typo. 


tro  face  ,,aqc  £r,4. 


CONSTRUCTION  OF  DIESEL  MARINE   ENGINE    265 

as  possible,  and  the  cover  has  been  kept  completely  free 
of  valves,  except  for  a  non-return  safety  valve  to  prevent 
excessive  compression.  Both  the  fuel  inlet  valve  and  the 
starting  valve  are  arranged  horizontally,  which  is  quite  a 
novel  construction. 

The  motor  is  of  the  enclosed  type  and  has  a  trunk  piston 
— a  design  which  will,  however,  not  prove  final,  especially 
for  the  larger  sizes,  although  even  in  a  so-called  enclosed 
type  the  parts  can  be  made  readily  accessible  by  removing 
the  light  covers  in  front  of  the  crank  chamber.  The  cylin- 
ders are  supported  by  steel  columns  in  a  somewhat  similar 
manner  to  the  Sulzer  marine  engine. 

The  pistons  of  the  motor,  contrary  to  usual  practice, 
are  not  provided  with  special  cooling,  and  in  order  to  prevent 
the  metal  becoming  overheated,  shield  plates  are  fitted, 
which  protect  the  body  from  the  greatest  temperature  ; 
but  this  arrangement  may  have  to  be  modified.  Reversing 
is  simplified  by  the  absence  of  valves,  and  for  each  fuel 
valve  three  cams  are  provided,  one  for  ahead,  one  for  astern, 
and  the  third  for  half  injection,  this  latter  being  a  novel 
feature.  The  actual  operation  of  reversing  is  carried  out 
by  means  of  a  large  hand- wheel,  which  can  be  seen  in  Fig.  138, 
representing  a  Tanner-Diesel  motor.  This  wheel  controls 
a  distributing  valve,  which  passes  over  three  ports  in  a 
three-cylinder  engine,  and  thus  admits  starting  air  to 
the  cylinders  one  after  the  other.  The  direction  of  rotation 
of  the  engine  on  starting  up  depends  on  ^^'hether  the  large 
hand- wheel  is  turned  to  the  left  or  right,  the  movement 
causing  one  of  two  valves  to  open  and  admit  air  to  the 
distributing  valve  as  desired.  In  the  normal  position  of 
the  hand- wheel,  the  air  supply  is  cut  off.  In  order  to  set 
the  fuel  cams  in  the  correct  position,  the  cam  shaft  is  auto- 
matically turned  through  an  angle  of  36°,  in  a  similar 
manner  to  that  adopted  in  the  M.A.N,  engines  already 
described. 

The  first  experimental  cylinder  built  to  Tanner's  designs 
was  of  19  in.  diameter  by  30  in.  stroke,  and  at  150  revolutions 
per  minute  developed  250-300  I.H.P. 


Fig.    139. — Experimental  Doxfoid  Diesel  Engine. 
266 


OONSTRIT'TTOX  O?  DTKl^EL  MARINE   EXGlNE   2G7 

In  order  to  make  the  engine  of  the  double-acting  type, 
another  cyUnder  would  be  arranged  above  the  first,  with 
a  piston  rod  connecting  the  two  pistons. 

The  Doxford  Diesel  engine,  as  built  by  Messrs.  Doxford 
&  Sons,  resembles  in  some  respects  motors  of  Continental 
design.  It  is  of  the  two-cycle  single-acting  type,  provided 
with  scavenge  valve  and  an  overhead  cam  shaft.  The 
single-cylinder  engine  illustrated  in  Fig.  139  is  of  19J  in. 
diameter  and  37  in.  stroke,  and  develops  about  250  B.H.P. 
at  130  revolutions  per  minute. 

Reversing  is  accomplished  by  turning  the  cam  shaft 
through  an  angle  of  38°  relative  to  the  crank  shaft,  and  as 
is  usual  in  this  class  of  engine  in  which  four  scavenge  valves 
are  used  per  c^^Knder,  these  are  operated  in  pairs  from  two 
cams  on  the  cam  shaft.  As  reversing  is  carried  out  by 
turning  the  cam  shaft,  two  separate  cams  and  rollers  are 
provided  side  by  side  for  operating  the  starting  air  valve, 
since  the  angle  turned  through  to  set  the  fuel  valve  cams 
is  insufficient  for  the  air  valves.  The  construction  of  this 
type  of  motor  has  no\\'  been  abandoned. 

Four-Cycle  Single  Acting  Engine  :  Dutch  Type.— ^ 
As  has  been  explained,  the  four-cycle  engine  is  milikely  to  be 
the  ultimate  solution  of  the  problem  of  the  Diesel  engine 
for  marine  work,  but  it  has  been  adopted  by  some  makers  as 
being  the  easiest  step  from  stationary  to  marine  work.  The 
marine  engine  constructed  by  the  Xederlandsche  Fabriek 
of  Amsterdam  is  of  this  type,  and  a  six-cyUnder  Werkspoor 
motor  of  500  B.H.P.  was  installed  by  this  firm  in  the  Vul- 
canus,  which  was  the  first  large  ocean-going  Diesel  engine 
propelled  vessel,  being  196  feet  in  length  and  having  a 
displacement  of  1,960  tons.  This  engine  is  illustrated  in 
Fig.  140,  M'liile  i^igr.  141  shows  a  cross-section  of  the  engine- 
room  of  the  vessel.  There  are,  as  is  almost  universal  with 
four-cycle  marine  engines,  four  valves  for  each  cylinder 
operated  in  the  usual  way  by  levers  actuated  by  cams  on  the 
horizontal  cam  shaft.  The  arrangement  for  reversing  in 
this  case  consists  of  having  two  perfectly  independent  cam 
shafts  A,  B  {Figs.  140  a7id  141)  of  which  one  (A)  has  on  it 


268    DIESEL  ENGINES  FOR  LAND  AND  MARINE  WORK 

the  cams  set  in  the  positions  for  operating  the  various 
valves  when  going  ahead,  and  the  other  (B)  carries  the 
reverse  cams.  These  two  shafts  are  supported  in  forked 
end  pieces  to  which  the  spindle  C  in  front  of  the  engine  is 
fixed.  This  spindle  may  be  turned  by  the  hand-wheel  D, 
which  by  the  link  motion  seen  in  Fig.  141  rotates  the  forked 
arms  around  the  spindle  C  and  so  brings  either  the  ahead 
or  astern  cam  shaft  in  the  position  to  operate  the  valve 
levers.  The  rotation  of  the  cam  shaft  is  obtained  from 
the  shaft  E,  which  carries  a  small  spur  wheel,  which  gears 
into  a  spur  wheel  on  each  of  the  cam  shafts,  and  thus  drives 
both  of  them  continual^  when  the  engine  is  running.  This 
might  be  considered  somewhat  of  a  disadvantage,  but  the 
power  required  to  drive  the  cam  shaft  which  is  running  idle 
is  practically  negligible  and  entails  no  trouble.  The  shaft  E 
is  itseK  driven  direct  off  the  crank  shaft  of  the  engine  from 
eccentrics  by  means  of  the  two  long  connecting  rods  which 
operate  the  shaft  E  by  means  of  two  small  cranks,  as  is  seen 
in  Fig.  140.  For  the  supply  of  fuel  to  the  fuel  valves  two 
small  horizontal  oil  pumps  F  are  used  driven  off  a  connecting 
rod,  but  only  one  of  them  is  in  operation  in  the  ordinary 
way.  This  design  is  contrary  to  the  means  usually  adopted, 
since  the  most  common  method  is  to  have  a  separate  pump 
for  each  cylinder.  The  pressure  of  the  oil  pumped  into  the 
valve  is  regulated  automatically  by  the  arrangement  G, 
which  operates  on  the  suction  valve  of  the  oil  pump,  much 
in  the  same  way  as  the  governor  lever  in  the  stationary 
engine,  no  governor  being  fitted  to  this  engine.  The  air 
compressor  for  the  injection  and  starting  air  is  of  the  three- 
stage  type,  and  is  driven  off  the  crossheads,  the  first  stage 
forming  a  separate  pump,  but  the  second  and  third  stage 
are  combined.  The  pumps  are  arranged  at  the  back  of  the 
engine,  the  high  pressure  cyHnder  being  seen  in  Fig.  141  ; 
water  cooling  is  adopted  between  all  the  stages.  Crossheads 
and  connecting  rods  are  adopted  for  this  engine  ;  hence  the 
piston  rod  is  short,  but  the  engine  is  relatively  higher  than 
ordinary  motors  of  the  four-stroke  type.  An  auxiliary 
compressor  is  installed  driven  by  a  stationary  type  two- 


[To  face  page  268. 


Fio.   140.— .-,0n  n.P.  Engine  tor  llie  Villi 


|7'o  face  page  268. 


CONSTRUCTION  OF  DIESEL  MARINE  ENGINE    269 

cylinder  Diesel  engine  of  50  H.P.  for  the  supply  of  starting 
and  manoeuvring  air,  and  also  the  air  which  is  used  for 
auxiliary  purposes.     Two  auxiliary  pumps  are  driven  direct 


bC 

a 


oft"  the  engine,  these  being  the  jacket  cooling  water  and  the 
bilge  pumps,  while  a  second  centrifugal  oil  pump  for  unload- 
ing the  oil  in  the  tanks  is  driven  off  the  auxiliary  engine 


270    DIESEL  ENGINES  FOR  LAND  AND  MARINE  WORK 

since  this  is  only  required  when  in  port.  The  oil  pump  for 
pumping  the  oil  up  to  the  tanks  is  also  driven  off  the  main 
engine  crank  shaft  by  means  of  an  eccentric.  A  small  10 
H.P.  oil  engine  coupled  direct  to  a  dynamo  provides  the 
electric  power  required  for  lighting  and  other  purposes. 
Forced  lubrication  is  adopted  for  the  main  engines,  and  the 
crank  chamber  is  enclosed  but  is  fitted  with  readily  remov- 
able cases  at  front  and  back,  these  being  seen  in  Fig.  140.  It 
vnW  be  noticed  that  in  general  design  this  engine  differs  but 
little  from  the  stationary  type  of  engine  manufactured  by 
the  Nederlandsche  Fabriek  previously  described,  except  in 
the  reversing  arrangement,  and  it  was  the  object  of  the 
designers  to  render  the  departures  from  marine  engine  prac- 
tice as  regards  steam  engines  as  few  and  unimportant  as 
possible. 

In  their  later  types  the  Nederlandsche  Fabriek  have 
slightly  modified  their  design  in  view  of  the  experience 
gained  with  the  first  large  engine.  The  six-cylinder  type 
is  adopted  for  all  engines  of  500  H.P.  or  above,  and  at  present 
the  largest  power  for  a  single  engine  is  1,100  B.H.P.  and 
the  limit  expected  is  about  2,000  H.P.  for  a  six-cylinder 
motor.  The  following  table  of  sizes  and  speeds  of  various 
engines  mil  be  useful,  one  only  being  a  high  speed  motor  of 
300  r.p.m.  for  a  small  gunboat.  All  the  engines  have 
six  cylinders. 


B.H.P.  of  Engine. 

Rev.  per  rain. 

Diam.  of  Cylindsr. 

Stroke  of  Piston. 

1,100 
850 
600 

125 

125 
300 

Mm. 
560 
520 
390 

:\im. 

1,000 
920 
500 

As  with  the  engine  previously  described,  the  larger  motors 
are  of  the  open  crosshead  type,  and  the  cylinders  are  sup- 
ported solely  by  vertical  steel  cylindrical  columns  some  two 
inches  in  diameter,  the  inclined  cast-iron  columns  being 


CONSTRUCTION  OF  DIESEL  MARINE  ENGINE    271 

mainly  for  the  purpose  of  taking  the  thrust  due  to  the  con- 
necting rod.  The  advantage  of  this  design  Hes  in  the  fact 
that  the  strength  of  the  columns  is  known  exactly,  whereas 
cast-iron  framing  is  always  to  a  certain  extent  an  unknown 
quantity.  Moreover,  the  bed-plate  can  be  made  lighter 
since  the  supporting  columns  are  closer  together,  and  the 


142.-250  H.P.   Werkspuor  Engine. 


bending  moment  is  less.  The  front  of  the  engine  is  then 
quite  open,  only  light  and  easily  removable  covers  being 
fitted,  and  the  arrangement  is  well  seen  in  Fig.  142,  which 
is  an  illustration  of  the  three-cvlinder  250  H.P.  encrine  of 
the  same  type  fitted  in  the  SemhUan,  and  in  Figs.  143  and 
144,  which  show  a  1,100  B.H.P.  motor. 
The  arrangement  of  valves  is  as  usual  in  a  four-cycle 


272   DIESEL  ENGINES  FOR  LAND  AND  MARINE  WORK 

engine,  there  being  four  in  the  cover  of  each  cyHnder.     The 
fuel  inlet  valve  which  is  in  the  centre  is  of  a  novel  construc- 


tion.    Instead  of  the  spring  holding  it  on  its  seat  being 
immediately  above  the  valve,  the  valve  lever  is  continued 


M'^ 


Fio.  14:!.— \\Vrlis[..».r  l.lcill  B.H.I'.  Diesel  Mot. 


Oudet  cooh/uj 
water 


Fig.   145. — Arrangement  of  Piston  Cooling  in  Werkspoor 
1,100  B.H.P.  Marine  Motor. 

273  'p 


Fig.   140.— Section  of  Werkspoor  1,100  B.H.P.  Four-Cycle  Marine  Motor. 

274 


CONSTRUCTION  OF  DIESEL  MARINE   ENGINE    275 

beyond  the  valve,  so  that  the  valve  serves  as  a  sort  of  ful- 
crum, the  spring  exerting  its  pressure  at  one  end  and  acting 
against  the  force  of  the  cam,  causing  the  lever  to  be  de- 
pressed at  the  other  end.  The  object  of  this  design  is  to 
render  the  removal  or  examination  of  the  fuel  valve  more  easy. 

In  principle,  the  reversing  arrangements  are  the  same  as 
those  of  the  engine  already  described,  but  the  detailed 
method  of  operation  is  quite  different.  All  the  gear  is 
arranged  in  the  centre  of  the  engine,  but  the  same  method 
of  driving  the  ahead  cam  shaft  is  employed,  three  long 
connecting  rods  coupled  to  eccentrics  fitted  on  the  crank 
shaft  being  used.  There  are  two  separate  cam  shafts,  one 
carrying  the  ahead  cams  and  one  the  astern  ;  these  are 
at  the  same  level  and  are  a  fixed  distance  apart,  but  are 
connected  together  with  gear  wheels,  so  that,  although  the 
ahead  cam  shaft  is  alone  driven  direct  from  the  crank 
shaft,  the  astern  cam  shaft  is  always  rotating.  The  bear- 
ings for  the  two  cam  shafts  are  supported  on  flat  guide  bases 
and  can  move  bodily  towards  or  away  from  the  engine, 
carrying  the  cam  shafts  with  them.  The  various  pairs  of 
bearings  are  cast  together,  so  that  they  must  move  at  the 
same  time,  and  the  relative  positions  of  the  cam  shafts 
never  vary.  The  bearings  in  the  centre  of  the  engine  are 
fixed  to  an  auxiliary  horizontal  spindle  behind  and  just 
below  the  cam  shafts,  and  if  this  spindle  rotates,  the  bearings 
and  cam  shafts  are  thus  moved  backwards  or  forwards, 
according  to  the  direction  of  rotation.  This  rotation  is 
effected  from  the  starting  platform  in  front  of  the  engine 
by  means  of  a  screw  and  link  motion,  either  operated  by  a 
small  air-engine  or  by  hand,  as  required.  It  was  originally 
intended  to  use  a  small  steam  engine,  but  this  was  found 
to  be  inadvisable. 

The  reversing  is  carried  out  quite  simply  by  means  of 
this  arrangement  in  about  twelve  seconds  from  full  speed 
ahead  to  full  speed  astern.  The  levers  are  lifted  clear  of 
the  cams,  the  cam  shafts  move  back  or  forward  as  the  case 
may  be,  the  levers  dropped  down  again,  and  the  engine  is 
then  ready  for  running  in  the  opposite  direction. 


o 


^ 


CONSTRUCTION  OF  DIESEL  MARINE   ENGINE    277 

In  other  details  the  engine  does  not  present  many  points 
of  difference  from  the  Vulcanus  motor.  The  lo^^•er  part  of 
the  cyhnder  is  bolted  on  to  the  main  casting  so  as  to  be 
readily  removable  in  order  to  examine  and  dismantle  the 
pistons,  and  this  means  is  certainly  an  advantage  for  marine 
work.  The  pistons  are  water  cooled,  and  the  exhaust 
pipe  consists  of  a  channel  of  large  rectangular  section,  which 
enables  a  silencer  to  be  dispensed  with.  It  was  desired  to 
use  exhaust  gases  for  heating  a  donkey  boiler,  which  provides 
steam  for  various  auxiliaries,  but  this  evidently  requires 
some  modification  in  the  boiler. 

The  Gusto  Motor. — This  is  an  engine  of  the  two-cycle 
single-acting  type  hitherto  built  in  relatively  small  sizes, 
that  is  to  say,  in  powers  of  350  H.P.  and  below.  It  is  mainly 
of  interest  in  that  it  is  one  of  the  few  Diesel  engines  of  the 
two-cycle  type  in  which  scavenging  by  means  of  ports  is 
employed  instead  of  the  utilization  of  valves.  In  the  type 
which  is  designed  for  powers  of  200  H.P.  or  below,  the 
construction  is  of  the  stepped  piston  type,  with  the  scavenge 
pump  arranged  below  each  working  cylinder  as  in  the  M.  A.X. 
engine,  but  in  the  larger  motors,  the  method  illustrated 
in  Fig.  149  is  adopted.  In  this,  although  the  scavenge  pump 
is  below  each  working  cylinder,  they  are  separated  b}"  means 
of  a  distance  framing,  which  has  the  advantage  that  the 
working  piston  can  be  drawn  out  from  below  the  heat 
cylinder  with  comparative  ease. 

As  no  scavenge  valves  are  recjuired,  there  is  only  the 
starting  valve  and  fuel  valve  in  each  cylinder,  and  in  this 
motor  a  special  construction  of  cylinder  is  adopted  in  which 
the  jacket  and  liner  are  cast  in  one  piece,  and  no  actual 
cyhnder  cover  is  fitted.  This  method,  although  suitable 
for  the  engine  under  discussion,  of  relativeh'  small  type, 
would  probably  be  undesirable  in  larger  motors. 

Referring  to  the  illustration,  1  represents  the  working 
cylinder  in  which  the  specially  shaped  top  can  be  noticed 
corresponding  to  the  shaping  of  the  piston.  This  is 
necessary  in  order  that  the  scavenge  air  which  enters  through 
the  port  10,  from  the  reservoir  7,  formed  in  the  framing, 


278    DIESEL  ENGINES  FOR  LAND  AND  MARINE  WORK 


Fig.   148. — Custu  Twu-Cycle  Marine  Mutor. 


may  be  deflected  upwards,  so  as  to  scavenge  out  the  whole 
of  the  contents  of  the  cyhnder,  which  are  exhausted  through 
port  11.  3  represents  the  cyhnder  of  the  scavenge  pump, 
and  4  its  piston,  whilst  8  is  a  piston  valve  controlling  the 


280    DIESEL  ENGINES  FOR  LAND  AND  ]VL4PvINE  WORK 

admission  of  scavenge  air  into  the  reservoir  7,  and  thence 
into  the  cylinder.  The  air  from  the  atmosphere  is  drawn  in 
through  tliis  piston  valve  to  the  scavenge  cylinder,  after 
which  it  is  compressed  and  the  port  then  allows  it  to  enter 
the  reservoir  7.  This  piston  valve  8  is  driven  by  means 
of  a  small  crank  9,  operated  from  an  auxiliary  horizontal 
shaft  which  also  drives  the  cam  shaft  13,  through  the  auxi- 
liary shaft  16. 

In  order  to  reverse  (for  the  motor  is  directly  reversible) 
the  camshaft  is  moved  eccentrically  in  its  bearing,  bringing 
the  cam  in  the  correct  position  for  astern  running.  The 
hand- wheel  15  has  the  function  of  setting  the  piston  valve 
of  the  scavenge  pump  in  the  correct  position  according  to 
the  direction  of  rotation  of  the  engine,  whilst  23  represents 
the  fuel  pump  which  may  be  controlled  by  means  of  the 
lever  seen  close  to  it,  thus  varying  the  speed  of  the  engine 
and  shutting  off  fuel  altogether  when  required.  A  two- 
stage  compressor  is  employed  driven  direct  from  the  end 
of  the  crank  shaft,  and  the  connecting  rod  5  and  the  crank 
6  are  of  the  usual  steam-engine  design.  The  motor  is  of  the 
enclosed  type,  as  forced  lubrication  is  adopted,  but  there 
are  wide  doors  which  are  readily  removable  by  hand. 

The  engine  has  been  adopted  for  a  number  of  relatively 
small  commercial  vessels  such  as  tug  boats  and  motor  coast- 
ing vessels,  and  it  runs  at  a  relatively  high  speed,  usually 
between  220  and  300  r.p.m.  Naturally  its  fuel  consump- 
tion is  not  so  satisfactory  as  that  of  small  four-cycle 
motors  and  the  construction  is  not  suitable  for  high  powers, 
but  for  its  purpose  it  appears  to  be  well  adapted. 

German  Types. — Several  firms  manufacture  a  four- 
cycle engine  for  marine  work  for  lower  powers,  and  almost 
invariably  employ  a  high  speed  engine,  which  differs  slightly 
from  the  stationary  type  of  high  speed  motor  which  has 
already  been  described.  Four  or  six  cylinders  are  employed, 
and  if  six,  the  engines  will  start  up  on  the  working  cylinders 
in  any  position  of  the  crank  shaft,  while  if  there  be  only 
four  cyUnders,  the  air  pump  must  be  arranged  to  be  used 
as  a  fifth  cylinder  for  starting  purposes  when  required. 


CONSTRUCTION  OF  DIESEL  MARINE  ENGINE   281 

At  the  Augsburg  works  of  the  Maschinenfabrik  Augsburg- 
Niirnberg,  four-cycle  engines  are  constructed  up  to  1,000 
B.H.P.  usually  of  four  cylinders  with  two  compressors  on 
the  end  of  the  bed-plate,  driven  direct  off  the  crank  shaft. 
An  engine  of  1,000  H.P.,  running  at  465  revolutions  per 
minute,  has  a  weight  of  only  about  45  lb.  per  B.H.P.  and  a 
fuel  consumption  of  about  "42  lb.  per  B.H.P.  hour.  With 
the  high  speed  engines,  it  is  customary  to  fit  a  safety  governor 
to  come  into  operation  in  case  of  emergency,  as,  for  instance, 
in  the  event  of  the  propeller  shaft  breaking,  and  so  prevent 
the  engine  running  awaj%  the  arrangement  adopted  being 
that  the  governor  acts  on  the  suction  valve  of  the  fuel  pump 
much  in  the  same  way  as  with  a  stationary  engine. 

In  the  Augsburg  engine  the  method  of  reversing  which 
has  been  employed  differs  somewhat  materially  from  tlie 
means  generally  used.  There  is  a  single  cam  shaft  provided 
with  separate  cams  for  the  forward  and  reverse  running,  for 
each  of  the  four  valves  on  all  the  cylinders,  but  these  cams 
do  not  actuate  the  valve  levers  direct,  as  is  customary. 
Instead  of  this,  the  nose  of  the  cam  lifts  a  small  roller,  of 
which  there  is  one  for  each  cam,  and  the  valve  lever  thus 
receives  its  up  and  down  motion  indirectly  from  the  cam 
through  the  roller.  Considering  any  single  valve,  there  is 
a  forward  and  reverse  roller,  both  of  which  are  attached  to  a 
drum  concentric  with  the  cam  shaft  and  capable  of  being 
turned  by  means  of  a  hand  lever,  and  of  width  equal  to  the 
combined  widths  of  the  two  cams.  In  the  position  of  the 
forward  running  the  "  forward  "  roller  is  down  on  its  cam  and 
the  "  reverse  "  roller  raised  out  of  range  of  its  cam  and  the 
valve  lever,  which  thus  receives  its  motion  from  the  forward 
cam.  To  reverse  the  engine  the  hand  lever  previously 
mentioned  is  moved  to  the  right  or  to  the  left,  thus  turning 
the  drum  carrying  the  rollers  through  a  certain  angle,  -with 
the  result  that  the  ''  forward  "'  roller  is  lifted  away  from  its 
cam,  whilst  the  "  reverse  "  roller  falls  on  to  the  reverse  cam 
and  actuates  the  valve  lever,  so  as  to  give  the  valve  its 
proper  timing  for  reverse  running.  Fig.  150  shows  a  four- 
cycle engine  of  the  Augsburg  type  of  850  H.P.  at  400  r.  p.m., 


282    DIESEL  ENGINES  FOR  LAND  AND  MARINE  WORK 


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this  being  designed  specially  for  submarine  work,  and  motors 
similar  to  this  type  have  been  fitted  to  submarines  for  the 
German  Navy. 


"' ii,i"-i"i''!  -;„'  "  ''M!iii|,i;i:nirr iijiiiii iiiii ii. wit liiLiJiiijiliHuliil i;iJi!i,i:ii!j.ijj:|jjjjj,;i!i!ijjliii!iii!i:ijijjjjjj:i:HJ!iiiMii|i|||i!i!iiiiiiiiiiii^ 


CONSTRUCTION   OF  DIESEL  MARINE   ENGINE    283 

For  powers  up  to  300  B.H.P.  Messrs.  Knipp  build  a  four- 
cycle engine  usually  of  six  cj'linclers  with  the  compressor 
mounted  on  the  end  of  the  motor,  driven  direct  off  the  crank 
shaft,  but  as  there  are  six  working  cylinders  it  is  unnecessary 
to  use  the  compressor  as  a  motor  when  starting  up.  The 
engine  is  of  the  totally  enclosed  high  speed  type,  very 
similar  to  that  adopted  for  stationary  work,  the  speed  for 
powers  between  about  150  and  300  B.H.P.  being  usually  in 
the  neighbourhood  of  400  revolutions  per  minute,  while  the 
weight  per  B.H.P.  varies  from  about  65  to  90  lb.  per  B.H.P. 
Reversing  is  carried  out  in  much  the  same  way  as  described 
for  the  two-cycle  engines  of  this  firm,  except  that  of  course 
an  exhaust  valve  is  used  and  this  has  also  to  be  reversed. 
By  an  ingenious  arrangement  in  which,  during  the  period  of 
running  on  compressed  air  when  starting  up,  the  exhaust  cam 
is  provided  with  two  more  nose  pieces,  the  engine  may  work 
as  a  two-cycle  air  motor  and  hence  the  torque  at  starting  is 
considerable,  and  the  manoeuvring  qualities  correspondingly 
improved. 

Danish  Type. — A  four-cycle  single  acting  engine  which 
has  been  developed  and  constructed  by  Messrs.  Burmeister 
&  Wain,  of  Copenhagen,  is  illustrated  in  Fig.  151,  this 
engine  being  of  1,250-1,500  I.H.P.,  installed  in  the  >SeZcmf/w, 
which  is  a  vessel  of  10,000  tons.  There  are  eight  cylinders, 
each  having  a  diameter  of  20 1  inches  and  a  stroke  of  28| 
inches,  the  normal  speed  of  revolution  being  130-140  revo- 
lutions per  minute.  The  engine  is  of  the  crosshead  type 
and  is  totally  enclosed  with  crank  chamber  doors,  \^  hich 
can  be  readily  removed  for  inspection.  The  general 
design  does  not  otherwise  present  many  marked  peculiar- 
ities, beyond  that  the  cylinders  are  divided  into  two  sets  of 
four,  which  is  found  to  be  a  convenient  design,  and  allows 
the  reversing  gear  to  be  arranged  in  the  centre,  so  as  to  be 
readily  operated.  A  further  difference  from  the  ordinary 
construction  is  in  the  position  of  the  cam  shaft,  which  is  on  a 
level  with  the  bottom  of  the  cylinders  instead  of  the  top, 
which  is  usually  the  case.  This  prevents  the  four  valves  in 
the  cover  being  operated  directly  from  the  cams  by  means  of 


284 


CONSTRUCTION   OF  DIESEL  MARINE   ENGINE    285 

short  levers,  and  necessitates  the  employment  of   the  long 
vertical  (or  nearly  vertical)  hollow  connecting  rods  seen  in  the 


bD 

c 


illustration.  It  may  be  mentioned  that  this  method  has  been 
adopted  by  some  other  manufacturers  in  their  four-cycle 
engines,  and  notably  Messrs.  Krupp,  who  do  not,  however, 


286    DIESEL  ENGINES  FOR  LAND  AND  MARINE  WORK 

build  large  engines  of  this  type.  When  this  design  is  em- 
ployed, it  is  of  the  utmost  importance  that  the  connecting 
rods  should  be  rigid,  as  their  motion  is  so  slight  for  opening 
the  valves  that  any  small  amount  of  play  is  most  undesir- 
able and  will  lead  to  some  trouble.  Lack  of  attention  to 
this  point  has  already  been  the  cause  of  much  difficulty  in 
some  engines. 

From  the  illustrations  it  can  be  seen  how  the  short 
horizontal  valve  levers  are  arranged  for  operating  the  valves, 
and  it  will  be  noticed  that  all  the  valves  open  downward, 
this  being  exceptional  for  the  fuel  inlet  valve,  which  usually 
opens  upwards.  The  former  method  somewhat  simplifies 
the  construction  and  apparently  gives  good  results  as 
regards    efficiency. 

In  the  earlier  pages,  the  general  means  of  reversing  Diesel 
engines  were  described,  and  the  arrangement  employed  by 
Messrs.  Burmeister  &  Wain  is  one  which  was  mentioned  as 
being  common — namely,  by  providing  side  by  side  a  separ- 
ate ahead  and  astern  cam  for  each  valve  on  the  cam  shaft, 
which  is  moved  in  a  longitudinal  direction  when  reversing 
the  engine,  so  as  to  bring  the  rollers  at  the  bottom  of  the  long 
connecting  rods  above  the  astern  cams.  The  distance 
which  the  cam  shaft  has  to  be  moved  is,  therefore,  equal  to 
the  width  of  the  cams,  and  the  motion  is  carried  out  in  a  novel 
way.  As  seen  in  the  front  elevation  in  Fig.  151,  slightly  to 
the  left  of  the  centre  of  the  engine,  there  is  a  wide  disc 
mounted  on  an  auxiliary  shaft,  in  which  a  slot  is  cut  about 
one- third  of  the  width  of  the  disc.  This  slot  slopes  from  the 
top  from  right  to  left,  and  another  disc,  nearly  equal  in 
width  to  that  of  the  slot  and  fixed  on  to  the  cam  shaft, 
fits  into  the  slot. 

The  auxiliary  shaft  can  be  turned  either  by  hand  or  by 
means  of  a  compressed  air  motor,  and  in  turning  it  causes  the 
disc  on  the  cam  shaft  to  move  to  the  right  or  left,  according 
to  the  direction  of  rotation,  and  hence  the  cam  shaft  itself 
is  likemse  moved  until  the  reverse  cams  are  in  the  required 
position.  Before  this  operation  is  carried  out,  the  rollers 
which  the  cams  lift  are  raised    above  the  cams,  and  are 


Fig.   1 


9  IruAm  \o~ 


Fia.    154.— Starting,  Inlpt,  niul  Fiul  \'n 


!.000  I.H.P.  Burmclst^r  A-  Wain  Jlarino  Diesel  Engir 


[To  lace  pngc  2Sli. 


CONSTRUCTION  OF  DIESEL  MARINE   ENGINE    287 

brouglit  down  again  when  the  cam  shaft  has  been  moved. 
The  lifting  of  the  rollers  is  accomplished  through  the  medium 
of  the  same  auxiliary  shaft,  which,  in  the  first  period  of  its 
rotation,  actuates  eccentrics  fixed  to  it.  These  are  connected 
by  short  connecting  rois  and  levers  to  the  bottom  of  thelong, 
vertical  rods,  which  transmit  the  motion  of  the  rollers  to 
the  horizontal  valve  rods. 

Only  the  high  pressure  stage  of  the  compressor  for  the 
provision  of  injection  air  is  mounted  on  the  engine,  this 
compressing  the  air  from  about  300  lb.  per  square  inch  up 
to  800—900  lb.  The  low  pressure  compressor  is  direct 
driven  from  an  auxiliary  stationary  type  Diesel  engine, 
which  has  also  coupled  to  it  a  dynamo  for  the  provision  of 
electric  power  for  lighting  and  auxiliaries.  This  low  pres- 
sure compressor  supplies  air  at  about  300  lb.  per  square  inch 
to  the  high  pressure  stage  on  the  engine,  and  also  provides 
the  air  for  manoeuvring  purposes.  In  a  twin-screw  vessel, 
as  the  Selandia,  two  auxiliary  sets  are  provided,  one  for  each 
engine,  and  there  is  also  usually  a  further  'steam-driven 
compressor  working  up  to  800-900  lb.  per  square  inch. 

The  exhaust  from  all  the  cylinders  of  the  engine  delivers 
into  a  common  D  shaped  pipe  and  thence  to  a  silencer, 
whilst  the  atmospheric  air  is  drawn  into  the  cylinders 
through  horizontal  inlet  slotted  pipes,  as  seen  in  the  illustra- 
tion, this  being  a  slight  modification  from  usual  practice 
where  vertical  inlet  pipes  are  employed. 

This  is  the  general  design  adopted  for  motors  up  to  about 
1,500  I.H.P.,  but  in  some  recent  engines  of  2,000  I.H.P. 
many  modifications  have  been  carried  out.  Engines  of  this 
power  are  made  with  six  cylinders,  having  a  bore  of  740 
mm.  (29  inches)  and  a  stroke  of  1,100  mm.  (43-4  inches), 
and  run  at  a  normal  speed  of  100  r.p.m.  The  main  point 
of  difference  lies  in  the  method  of  supporting  the  cyUnders, 
for  in  the  larger  engines  instead  of  having  a  continuous 
framing,  made  of  four  pieces  and  bolted  together,  there 
is  an  A  frame  of  very  heavy  construction  over  each 
bearing,  and  the  cylinder  jackets  of  the  six  cylinders  are 
cast  in  pairs  of  three  each  with  feet  which  are  bolted  direct 


Sale     of  Metns 

Fig.    155. — Section    of    Six-Cylinder    Burmeistar    &    Wain 
2,000    I.H.P.  Marine  Engine. 

288 


CONSTRUCTION  OF  DIESEL  AIARINE  ENGINE    289 

to  the  top  of  the  A  framing.  In  the  front  of  the  engine, 
Hght  doors  are  fitted  between  the  standards  ^^•hich  are  oil- 
tight  (since  forced  lubrication  is  adopted  as  with  the  other 
motors),  but  are  readily  removable  so  that  the  engine, 
when  they  are  taken  away,  is  practically  of  the  open  type. 
Between  the  upper  portions  of  the  standards,  however, 
stiffening  pieces  are  bolted  to  which  the  crossheads  guides 
are  fixed,  and,  moreover,  there  are  steel  columns  running 
right  through  from  the  bottom  of  the  bed-plate  to  the 
cylinder  covers  through  the  cyUnder  jackets,  which  serve 
to  support  the  cylinder  head.  On  theto23  of  the  A  standard 
a  light  cover  is  fitted  to  the  cylinder  through  which  the 
piston  rod  passes  by  means  of  a  suitable  gland.  There  is 
a  tray  fixed  in  this  cover  so  that  any  lubricating  oil  dropping 
from  the  piston  does  not  mix  with  the  oil  circulating  in  the 
crank-chamber,  but  can  be  carried  away  and  filtered  and  used 
over  again.  With  this  design  of  cylinder  and  framing  a 
more  accessible  construction  of  cylinder  is  obtained. 

Instead  of  having  only  the  high  pressure  stage  of  the  air 
compressor  driven  direct  from  the  engine  as  in  the  motors 
previously  described,  in  the  larger  type  all  three  stages 
are  directly  driven.  An  auxiliary  compressor  is  of  course 
provided  in  a  ship  if  equipped  with  this  arrangement. 
Starting  is  accomplished,  however,  in  the  same  way  at  a 
lower  pressure  than  that  ordinarily  adopted,  360  lb.  per  sq. 
inch  being  the  usual  pressure  employed.  Instead  of  having 
a  single  fuel  pump  for  all  the  cylinders  there  is  a  separate 
one  for  each  cylinder  in  the  larger  motor,  and  this  is  natur- 
ally an  improvement  in  design,  especially  from  the  point 
of  view  of  safeguarding  against  breakdo^viis,  or  a  consider- 
able loss  of  power. 

A  new  type  of  bed-plate  is  also  employed  very  similar 
to  the  bed-plate  of  a  marine  steam  engine,  and  is  open  at  the 
bottom  instead  of  enclosed  as  with  the  smaller  engines.  To 
it,  however,  throughout  the  whole  of  its  length  is  bolted 
a  tray  in  order  to  collect  the  oil.  In  the  smaller  engines 
oil  is  used  for  cooling  the  piston,  this  being  recooled  itself 
by  a  circulation  of  sea  water  around  the  oil  cooler ;  but  in 

u 


290    DIESEL  ENGINES  FOR  LAND  AND  MARINE  WORK 

the  larger  motors,  owing  to  excessive  amount  of  oil  which  is 
required  and  the  difficulty  of  cooling  such  a  large  quantity, 
sea  water  alone  is  employed,  being  pumped  directly  into 
the  piston  which  it  reaches  by  means  of  a  telescopic 
pipe. 

The  methods  of  operating  the  valves  and  the  reversing 


Fig.    156. — 2,000  I.H.P.  Burmeister  &  Wain  Marine  Diesel  Engine,  show- 
ing intermediate  shaft  and  push  rods  for  operating  the  Valves. 

system  are  practically  unaltered,  the  cam  shaft  as  before 
being  low  down  so  that  long  tappet  rods  are  necessary. 
There  are  also  two  sets  of  cams  for  every  valve,  one  for 
ahead  and  one  for  astern,  and  the  cam  shaft  is  moved  length- 
ways to  the  engine  so  as  to  bring  the  correct  cams  under- 
neath  the   tappet  rods.     The  cam  shaft,  however,  is  not 


CONSTRUCTION  OF  DIESEL  MARINE  ENGINE    291 

driven  by  connecting  rods,  but  by  means  of  two  spur  wheels 
which  seems  to  be  a  more  accurate  and  reHable  method. 

This  motor  is  of  special  interest  owing  to  its  dimensions, 
which  are  very  large  for  a  four-cycle  engine,  and  also  for 
the  lo.v  speed,  namely  100  r.p.m.,  which  is  naturally  very 
desirable  in  order  to  obtain  an  efficient  propeller. 

No  difficulties  appear  to  have  been  encountered  in  the 
operation  of  these  engines,  and  it  is  possible  that  even  larger 
sizes  may  be  built,  although  probably  the  limit  in  economy 
of  construction  has  almost  been  reached  with  motors  of  this 
power. 

Russian  Types. — Owing  to  the  abundance  of  oil  in 
Russia  some  considerable  progress  has  been  made  in  the 
employment  of  Diesel  engines  for  all  purposes.  For  several 
years  boats  have  been  running  in  Russian  waters  equipped 
with  Diesel  engines.  However,  in  most  cases,  ordinary 
stationary  motors  have  been  supplied  and  some  type  of 
reversing  mechanism  employed,  either  mechanical  or  elec- 
trical. 

Two  firms  are  now  engaged  in  the  construction  of  the 
engine,  Messrs.  Nobel  Bros,  and  the  Kolomna  Co.  In  both 
cases  the  greatest  attention  has  been  paid  to  the  four-cycle 
engine,  although  the  two-cycle  motor  is  now  being  developed. 
Up  to  the  present,  the  engines  built  by  Nobels  have  mostly 
been  of  the  high  speed  tj^pe,  varying  from  400  B.H.P.  and 
250  revolutions  per  minute  to  120  B.H.P.  and  450  revolutions 
per  minute,  although  there  is  a  type  of  400  or  500  B.H.P. 
and  310  revolutions  per  minute. 

The  motor  is  of  the  enclosed  type,  the  chambers  being 
mounted  on  a  crank  chamber,  and,  unlike  some  other 
designs  of  four-cycle  engines,  the  cam  shaft  is  overhead. 
Engines  up  to  1,000  H.P.  are  built  of  the  four-cycle  tjrpe. 

The  method  of  reversing  adopted  for  this  engine  is  some- 
what different  from  that  employed  in  all  other  4-cycle  motors. 

There  are  two  cams  for  each  valve  as  usual,  but  instead  of 
sliding  the  cam  shaft  along  in  order  to  bring  the  cams  under 
the  valve  lever  roller,  this  lever  is  provided  with  two  rollers. 
When  the  hand- wheel  is  turned  to  bring  about  the  reversing 


294    DIESEL  ENGINES  FOR  LAND  AND  MARINE  WORK 

of  the  motor,  the  roller  of  the  valve  lever  immediately  above 
the  astern  cam  is  brought  down  on  to  this  cam,  whilst  the 
ahead  cam  is  kept  well  out  of  range.  In  some  motors, 
however,  built  by  Nobels,  the  ordinary  methods  of  reversing 
is  adopted  by  moving  the  cam  shaft  longitudinally.  This 
method  is  mostly  employed  for  the  smaller  engines,  as  in  the 
larger  sizes  the  shifting  of  the  cam  shaft  by  hand  becomes 
too  difficult  a  matter. 

The  engines  built  by  the  Kolomna  Company  are  also  of  the 
four-cycle  type,  and  have  been  constructed  up  to  1,000  H.P., 
the  engines  illustrated  in  Figs.  157  and  158  being  respectively 
of  250  and  600  B.H.P.  These  engines  are  of  relatively 
high  speed,  and  in  some  ways  resemble  the  Nobel  con- 
struction. 

The  method  of  reversing  is  a  novel  one.  Above  the  cam 
shaft  are  two  separate  spindles  on  which  are  pivoted  the  vari- 
ous levers  for  operating  the  valves.  When  it  is  desired  to 
reverse  the  motor,  the  levers  seen  in  the  illustration  at  the 
front  of  the  engine  are  turned  to  an  angle  of  45°,  which 
operation  rises  the  fuel- valve  lever  of  the  cam  and  puts  the 
fuel  pumps  out  of  operation,  so  that  no  fuel  can  be  admitted 
to  the  cylinders.  The  same  action  admits  air  into  two 
small  air  cylinders  seen  above  each  of  the  working  cylinders, 
these  being  fitted  just  over  the  air  inlet  and  exhaust  valves 
in  each  cylinder.  These  cylinders  act  as  air  motors,  in  which 
the  piston,  being  forced  do^A^lwards  by  the  admission  of  air, 
causes  the  valve  levers  of  the  exhaust  valve  and  fuel  inlet 
valve  to  be  raised  off  their  cams.  This  having  been  done, 
the  cam  shaft  is  then  able  to  move  longitudinally,  and  the 
reverse  cams  are  brought  underneath  the  various  valve 
rod  levers.  The  rollers  of  the  levers  are  then  once  more 
brought  down  on  to  their  cam  and  the  engine  is  in  a  position 
for  reverse  running.  The  motor  is  started  up  by  compressed 
air,  before  the  fuel  valve  lever  is  dropped  down  on  to  its  cam 
and  fuel  admitted  into  the  cylinders.  In  the  larger  engines 
all  these  operations  are  carried  out  by  compressed  air  in 
the  usual  way,  but  in  the  smaller  type  it  is  thought  better 
to  effect  the  various  movements  by  hand. 


CONSTRUrTTON   OF  DIESEL  MARINE  ENGINE    295 

Small  Diesel  Marine  Engines. — At  the  present  time 
it  may  be  said  that  the  minimum  limit  for  Diesel  engines 
from  a  commercial  point  of  view  for  land  work  is  about  50 


B.H.P.,  below  which  power  it  is  generally  found  advisable 
to  employ  a  motor  of  lower  first  cost  even  though  the  fuel 
consumption  is  higher.  There  are  one  or  two  exceptions 
to  this  such    as    small  horizontal  motors  which  are  made 


29G    DIESEL  ENGINES  FOR  LAND  AND  MARINE  WORK 

in  such  large  numbers  as  to  reduce  the  cost  of  construction 
and  put  the  engines  on  a  par  from  the  point  of  view  of  cost 
with  other  types  such  as  the  hot  bulb  engine. 

For  marine  work  it  has  generally  been  thought  that  the 
Diesel  engine  is  hardly  particularly  applicable  below  powers 
of  about  200  H.P.,  mainly  again  owing  to  the  first  cost,  and 
also  because  of  the  greater  simplicity  of  other  types.  There 
are,  however,  many  engines  of  100  H.P.  and  upwards 
designed  to  be  specially  suitable  for  installation  in  craft 
requiring  about  this  power  for  their  propulsion.  These 
need  not  be  discussed  at  length  as  they  have  none  of  them 
received  wide  application  and  have  in  fact  only  been  adopted 
in  special  instances  where  they  have  particular  advantages. 
It  must,  however,  be  remembered  that  this  type  of  motor 
will  probably  make  much  more  headway  in  the  future, 
particularly  if  it  be  designed  as  simply  as  possible  so  that 
it  may  be  operated  by  unskilled  men,  and  may  be  con- 
sidered equally  reliable  with  other  engines  which  are  com- 
monly installed  in  moderate  size  motor  craft. 

These  small  Diesel  motors  have  been  built  both  of  the 
four  and  two-cycle  type,  and  in  spite  of  the  higher  fuel 
consumption  it  is  probable  that  the  latter  design  will  find 
most  favour  owing  to  the  greater  simplicity  which  is  per- 
haps the  essential  point  in  the  construction  of  an  engine 
working  on  this  principle. 

One  of  the  four-cycle  engines  which  has  been  manufac- 
tured on  a  fairly  large  scale  is  the  Daimler  type,  which  is 
constructed  largely  of  bronze  in  order  to  reduce  the  weight, 
for  heaviness  is  usually  one  of  the  disadvantages  of  the 
small  Diesel  engine.  The  four-cylinder  set  shown  in  Fig. 
159  has  a  cylinder  diameter  of  200  mm.,  a  stroke  230 
mm.,  and  when  running  at  530  r.p.m.  develops  about 
100  B.H.P.  It  is  made  directly  reversible,  and  weighs 
only  about  45  cwt.  complete,  which  appears  to  be  about 
the  limit  in  lightness  for  a  Diesel  motor  of  the  four-cycle 
type  of  this  power.  There  is  nothing  peculiar  in  the  design 
apart  from  the  fact  that  the  cylinder  covers  are  cast  in  pairs, 
and  that  there  is  an  extra  valve  to  each  cover  for  reversing, 


298    DIESEL  ENGINES  FOR  LAND  AND  MARINE  WORK 

which  of  course  is  carried  out  by  means  of  compressed  air. 
Reversing  is  accomplished  by  shding  the  cam  shaft  longitudi- 
nally in  the  usual  manner,  this  shaft  being  provided  with 
two  cams  for  each  valve,  one  of  which  operates  the  valve 


lever  when  going  ahead  and  the  other  w^hen  running  astern. 
In  Fig.  160  is  illustrated  another  four-cycle  motor  also  of 
100  B.H.P.  in  six  cylinders,  this  being  of  the  Krupp  design. 
It  has  a  speed  of  revolution  of  SCO  r.p.m.,  but  is  not  quite 
so  light  a  construction  as  the  motor  previously  described. 


300    DIESEL  ENGINES  FOR  LAND  AND  MARINE  WORK 

It  is  not,  however,  directly  reversible,  and  its  only  peculiar 
feature  lies  in  the  method  of  operating  the  valves,  the 
cam  shaft  being  low  down  and  the  valve  rockers  actuated 
through  the  intermediary  of  long  vertical  push  rods. 

Among  the  small  two-cycle  engines  constructed  is  one 
of  the  Junkers  design  illustrated  in  Fig.  161.  This  is  a  two- 
cylinder  motor  of  100  B.H.P.  running  at  about  300  r.p.m_., 
the  third  vertical  cylinder  being  the  scavenge  pump.  The 
principle  of  operation  of.  this  motor  is  the  same  as  that 
described  earlier  in  connexion  with  the  Junkers  large  engine, 
there  being  two  opposed  pistons  in  each  cylinder  with  the 
fuel  inlet  valve  horizontal  in  the  middle  of  the  cylinder. 
This  engine  is  said  to  give  the  particularly  low  fuel 
consumption  of  about  0-41  lb.  per  B.H.P.  hour. 

Fig.  162  shows  a  four-cylinder  two-cycle  motor  which 
has  recently  been  developed  in  America  by  the  Gas  Engine 
&  Power  Co.  In  this  case  the  motor  is  of  somewhat 
slightly  larger  size  than  those  previously  described  ;  the 
dimensions  of  the  cylinders  are  9  inches  bore  by  12 
inches  stroke,  the  speed  of  rotation  being  2£0  to  300 
r.p.m.,  whilst  the  power  is  about  150  to  175  B.H.P. 
The  motor  is  directly  reversible,  and  reversing  is  provided 
for  by  having  two  cams  for  each  valve,  one  for  ahead  and 
one  for  astern  as  in  the  previous  cases.  It  will  be  noticed 
also  with  this  engine  that  long  push  rods  are  employed 
with  a  low  cam  shaft.  In  each  cylinder  cover  are  two 
scavenge  valves  besides  the  usual  starting  valve,  fuel  valve 
and  relief  valve.  There  is  a  single  scavenge  pump  driven 
direct  off  the  end  of  the  crank  shaft,  and  the  two-stage  air 
compressor  is  driven  by  means  of  a  lever  from  the  crosshead 
of  this  scavenge  pump. 

Another  two-cycle  reversible  motor  which  has  been 
employed  to  a  certain  extent  in  fishing  vessels  and  small 
commercial  craft  is  the  Kind  engine,  a  six-cylinder  design 
being  shown  in  Fig.  163.  This  motor  is  one  of  150  B.H.P. 
running  at  about  300  to  350  r.p.m.  It  is  arranged  with 
the  scavenge  pumps  directly  below  the  working  piston,  the 
usual  stepped  piston  being  adopted    as    with  other  high- 


CONSTRUCTION  OF  DIESEL  MARINE   ENGINE    301 

speed  engines  such  as  the  M.A.N,  and  the  F.I.A.T.  submarine 
motors.     There  is  a  single  scavenging  valve  in  the  cyhnder 


cover  besides  the  fuel  valve  and  starting  valve,  no  relief 
valves  being  provided  with  this  engine. 


CHAPTER    VIII 
THE  DESIGN  OF  DIESEL  ENGINES 

CYLINDERS    AND      CYLINDER     COVERS PISTONS ^CYLINDER 

DIMENSIONS — CRANK        SHAFTS AIR      COMPRESSORS 

SCAVENGING    PUMPS 

It  is  quite  impossible  to  develop  the  design  of  Diesel 
engines  along  such  lines  as  would  apply  generall}^,  owing 
to  the  fact  that  the  many  different  types  vary  considerably 
in  important  matters  of  construction,  and  not  only  in  detail. 
In  the  first  place,  of  course,  four-cycle  and  two-cycle  engines 
must  be  treated  separately,  and  in  each  essential  type  we 
have  differing  methods  of  driving  the  air  compressors, 
different  arrangements  for  the  scavenge  pump,  and  other 
variations,  so  that  the  efficiencies  in  the  several  types  are 
by  no  means  the  same.  These  facts  must  be  borne  in  mind 
when  using  the  formulae  and  rules  given  later  for  calculation, 
and  allowance  made  for  the  peculiarities  presented  by  any 
special  type  of  engine. 

Cylinders  and  Cylinder  Covers. — The  cylinder  covers 
and  liners  of  a  Diesel  engine  form  perhaps  the  most  vulner- 
able portions  of  the  motor.  They  are  now  practically 
invariably  constructed  of  close  grained  cast  iron,  although 
in  several  marine  engines  of  the  two-cycle  type  cast  steel 
was  employed  for  the  covers,  but  this  in  practice  was  found 
to  be  unsuitable  and  to  give  rise  to  cracks.  It  has  therefore 
been  almost  entirely  discarded,  and  will  probably  not  be 
employed  in  the  future,  although  there  is  a  possibility  that 
it  may  be  utilized  for  very  large  motors  in  which  a  totally 
different  design  from  the  ordinary  is  adopted.  In  motors 
for  submarines,  steel  has  also  been  brought  into  use. 

It  might  be  thought  that  the  first  essential  reason  for 
cylinders  designed  for  great  strength  in  Diesel  engines  would 


THE  DESIGN  OF  DIESEL   ENGINES  303 

be  owing  to  the  high  pressure  of  compression  and  combus- 
tion in  the  cyhnder  itself.  Probably,  however,  the  most 
important  point  is  the  rapid  fluctuation  of  heat  through 
the  cylinder  liner,  and  the  consequent  stresses  which  are 
set  up  in  it.  These  stresses  naturally  increase  as  the  dia- 
meter of  the  cylinder  increases,  and  it  is  easy  to  see  that 
owing  to  the  great  heat  on  the  inside  of  the  Hner,  expansion 
takes  place,  whilst  the  outside  is  cooled  by  the  cooling  water, 
so  that  excessive  stress  may  result. 

When  it  is  considered  that  in  a  two-cycle  engine  with  a 
cylinder  of  say  30  inches  in  diameter,  the  thickness  of  the 
liner  has  to  be  about  3  to  3|  inches,  it  is  not  difficult  to 
understand  that  trouble  may  result,  and  this  is  indeed  one 
of  the  points  which  increase  the  difficulty  of  the  design  of 
very  large  Diesel  engines.  Apart,  however,  from  the  ques- 
tion of  the  regularly  alternating  stresses,  owing  to  the  high 
temperature  to  which  the  material  of  the  cylinders  is  con- 
tinuously exposed,  there  is  a  possibility  of  what  is  commonly 
called  "  growth  "  of  the  cast  iron  which  is  of  course  a  well- 
known  factor  in  other  directions,  particularly  in  regard  to 
steam  turbine. 

In  a  two-cycle  engine,  the  fluctuation  of  heat  is  twice 
as  rapid  as  in  a  four-cycle  motor,  and  indeed  in  the  latter 
type  comparatively  little  trouble  has  been  experienced  in 
the  matter  of  cracked  cyhnder  liners  or  cracked  covers, 
which,  however,  is  not  the  case  with  two-cycle  engines. 
The  following  remarks  therefore  apply  more  particularly 
to  the  two-stroke  type  of  Diesel  engine. 

No  matter  what  the  design  may  be,  it  is  impossible  to 
avoid  very  severe  stresses  in  covers  and  liners  of  two-cycle 
motors,  and  the  designer  has  therefore  only  to  aim  at  dimin- 
ishing these  stresses  so  far  as  possible,  by  a  careful  examina- 
tion of  the  causes  which  give  rise  to  them.  Even  from  the 
very  earliest  experiments  which  Dr.  Diesel  made  on  his  first 
engines  it  was  apparent  that  the  shape  of  the  combustion 
chamber  had  an  important  effect  upon  the  reliability  of  the 
Diesel  motor.  Later  experience  has  more  clearly  shown 
that  it  is  essential  for  the  combustion  chamber,  so  far  as 


THE   DESIGN  OF  DIESEL  ENGINES  305 

possible,  to  be  enclosed  by  plane  surfaces  and  that  all  pockets 
and  projections  should  be  avoided.  Moreover,  the  ratio 
between  the  cooling  surface  enclosing  the  combustion 
chamber  to  the  total  volume  of  the  chamber  should  be  as 
large  as  possible  in  order  to  maintain  good  cooling  effect. 
This  point  has  been  overlooked  in  some  designs  which  other- 
wise showed  great  possibilities. 

The  stresses  caused  in  the  cylinder  cover  are  greatest 
nearest  the  point  where  combustion  is  at  its  maximum,  and 
therefore  it  is  desirable  to  arrange  the  necessary  valves  in 
the  cover  as  remote  from  this  point  of  maximum  combus- 
tion as  is  possible  and  practicable ;  for  the  points  where 
the  casting  is  weakest  are  naturally  those  where  it  has  been 
pierced  in  order  to  accommodate  the  various  valves.  It  is 
obviously  desirable,  therefore,  to  space  these  valves  as  far 
apart  as  possible,  and  above  all  to  limit  their  number  to 
the  absolute  minimum.  This  naturally  points  to  the  great 
superiority  of  an  engine  in  which  a  number  of  the  usual 
valves  are  dispensed  with,  and  in  this  category  may  be 
placed  the  tw^o-cycle  motor  in  which  scavenge  ports  are 
employed  instead  of  scavenge  valves.  Experience  has 
already  shown  that  W'here  such  a  design  is  adopted  the 
danger  of  the  cracking  of  the  cylinder  cover  and  cylinder 
liner  is  not  so  marked  as  with  the  valve  scavenging 
engine.  This  question  is  further  discussed  later.  Apart 
from  the  stresses  which  are  produced  both  by  the  pressure 
in  the  working  cylinder,  and  also  the  stresses  due  to  the 
heating,  there  are  those  arising  in  the  ordinary  way  during 
the  casting,  but  by  modern  methods  these  can  be  kept 
within  a  reasonable  margin. 

It  is  not  possible  to  calculate  theoretically  the  thickness 
of  a  cylinder  liner  which  is  necessary  in  a  Diesel  engine 
owing  to  the  fact  that  the  chief  stress  (which  as  men- 
tioned above  is  that  due  to  heat  and  not  to  pressure)  cannot 
be  precisely  determined.  If  the  liner  is  made  too  thick 
the  stresses  due  to  heat  which  increase  with  the  thickness 
of  the  liner  beyond  a  certain  point,  may  be  so  augmented 
as   actually   to   counter-balance   the   diminution   of   stress 

X 


306    DIESEL  ENGINES  FOR  LAND  AND  MARINE  WORK 

due  to  pressure,  so  that  the  resultant  stress  is  greater  by 
an  increase  of  thickness.  This  does  not  apply  to  rela- 
tively small  engines,  but  it  is  not  difficult  to  see  that  it 
might  be  the  case  in  regard  to  very  large  motors.  In  fact 
it  would  seem  that  when  we  come  to  engines  which  have 
to  develop  say  1,500  H.P.  per  cylinder  or  more  it  might  be 
desirable  to  adopt  a  totally  different  design  of  cylinder  liner, 
and  to  have  an  inner  liner  which  is  relatively  thin  (say  one 
inch  in  thickness)  so  as  to  allow  the  rapid  transference 
of  the  heat  from  the  interior  to  the  exterior  of  these  walls. 
Outside  of  the  first  liner  another  barrel  with  web  could  be 
shrunk  on,  and  take  the  stresses  due  to  the  pressure.  An 
arrangement  of  this  sort  was  proposed  to  the  author  by 
Mr.  Thunholm  and  seems  to  offer  great  possibilities,  although 
there  are  various  methods  by  which  the  same  principle 
could  be  carried  out. 

Pistons  .^ — Owing  to  the  high  compression  in  a  Diesel 
engine  cylinder  and  the  obvious  necessity  for  the  absolute 
prevention  of  any  leakage  with  the  consequent  loss  of  com- 
pression, the  piston  rings  have  to  be  made  with  special 
care.  There  are  usually  five  to  seven  of  these,  generally 
of  cast  iron,  and  perhaps  the  best  construction  is  that  com- 
monly adopted  for  all  rings  which  have  to  preserve  tightness 
against  a  heavy  pressure.  With  the  old  method  of  ham- 
mering it  is  difficult  to  prevent  some  eccentricity  in  the  ring, 
which  naturally  may  cause  unequal  wear  on  the  cylinder 
walls.  In  the  design  referred  to,  the  ring  after  being  cut 
(having  then  no  spring)  is  fixed  in  a  die  which  is  slowly 
rotated,  and  is  struck  on  the  inner  side  by  a  light  chisel- 
pointed  hammer.  The  strength  of  the  blow  is  varied  auto- 
matically, being  maximum  at  the  side  of  the  ring  remote 
from  the  cut  and  minimum  near  the  cut.  The  width  of  the 
face  of  the  hammer  is  slightly  less  than  the  depth  of  the 
ring.  After  the  process,  the  ring  is  found  to  have  sufficient 
elasticity  for  the  purpose,  is  perfectly  round  and  certainly 
gives  excellent  results  in  operation. 

The  piston  is  a  detail  of  the  Diesel  engine  which  requires 
special   attention  in  its   design   and   construction   mainly 


THE  DESIGN  OF  DIESEL  ENGINES 


307 


omng  to  the  high  temperatures  in  the  cyhnder  and  also 
because  of  the  excessive  pressures  involved.     It  is  usually 


308    DIESEL  ENGINES  FOR  LAND  AND  MARINE  WORK 

made  to  taper  slightly  from  the  top,  and  is  of  course  always 
of  cast  iron.  A  good  clearance  is  allowed  around  the 
portion  where  the  gudgeon  pin  enters,  and  where  there  is 
necessarily  an  extra  thickness  of  metal,  in  order  that  the 
greater  expansion  may  not  cause  it  to  bend  on  the  cylinder 
walls.  The  gudgeon  pin  is  made  a  tight  fit,  is  keyed  and 
often  locked  by  means  of  a  set  screw,  the  pin  having  a  hole 
through  the  centre  to  allow  the  passage  of  lubricating  oil 
from  the  cylinder  walls.  It  is  desirable  that  the  gudgeon 
pin  be  placed  as  low  as  possible  so  as  to  be  away  from  the 
zone  of  greatest  heat. 

The  lubrication  of  the  piston  is  carried  out  by  admitting 
oil  from  sight  feed  lubricators  or  other  means  through  two 
or  more  connexions  passing  right  through  the  cylinder 
jacket.  For  small  cylinders  (up  to  about  15  inches  in 
diameter)  two  are  satisfactory,  but  above  this  size  there 
should  be  four  and  for  large  cylinders  six  or  even  eight. 
For  marine  engines  it  is  very  desirable  that  each  pair  should 
be  supplied  by  separate  plunger  pumps  so  that  any  failure 
should  not  cut  off  all  the  lubricating  oil  to  a  cylinder. 

As  a  general  rule  it  may  be  taken  that  the  thickness  of 
the  liner  for  a  Diesel  engine  of  the  four-cycle  type  varies 
between  0-085  and  O-IO  of  the  cylinder  diameter,  whilst 
in  a  two-stroke  engine  it  is  between  0-10  and  0-125  of  the 
diameter.  The  exact  ratio  depends  to  a  large  extent  upon 
the  experience  which  each  particular  firm  has  had  in  the 
construction  of  such  parts  and  the  maximum  intensity  of 
stress  which  in  consequence  they  feel  justified  in  allowing. 
Up  to  the  present  in  the  very  large  two-cycle  engines  which 
have  been  employed  for  sea-going  work,  the  cylinder  liners 
have  been  generally  rather  thicker  than  necessary,  and  the 
highest  figure  given,  namely  0-125,  has  been  frequently 
adopted.  In  four-cycle  engines  the  thickness  increases 
as  a  rule  with  the  diameter  (that  is  to  say  the  ratio  of  liner 
thickness  to  the  cylinder  diameter),  but  the  variation  is  not 
very  marked,  largely  owing  to  the  experience  which  has 
been  gained  with  four-cycle  motors  in  the  past. 

It  has  been  found  that  in  order  to  diminish  the  stresses 


THE   DESIGN   OF   DIESEL   ENGINES  309 

resulting  from  the  transference  of  lieat,  an  extremely 
desirable  feature  in  an  engine  is  that  this  heat  shall  be 
rapidly  conducted  to  other  remote  parts  of  the  machine. 
From  this  point  of  view  the  cylinder  cover  as  ordinarily 
designed  is  of  course  very  badly  placed,  and  one  of  the 
advantages  of  a  design  adopted  by  Messrs.  Krupp  for  large 
two-cycle  marine  engines  and  the  Werkspoor  firm  for 
four-cycle  engines  in  which  the  cover  is  in  one  piece  with  a 
liner,  lies  in  this  fact.  It  has  obvious  corresponding  dis- 
advantages, since  the  whole  cover  and  liner  must  be  replaced 
if  one  part  is  cracked,  and  the  question  of  the  relative  value 
of  the  methods  is  no  doubt  largely  one  of  personal  preference. 

Needless  to  say  the  penetration  of  the  liner  in  order  to 
accommodate  valves  is  quite  as  detrimental  as  carrpng 
out  the  same  purpose  by  utiUzing  valves  in  the  cyhnder 
cover,  and  this  is  one  of  the  unsatisfactory  features  of 
engines  which,  like  the  Junkers  type,  have  fuel  and  other 
valves  entering  into  the  liner.  It  is  also  an  argument 
against  the  horizontal  fuel  injection  valve  which  has  been 
adopted  in  one  or  two  designs. 

Cylinder  Dimensions. — A  good  deal  of  latitude  is 
allowed  the  designer  in  calculating  the  cyhnder  dimensions 
for  a  Diesel  engine.  Taking  the  ordinary  four-cycle  Diesel 
engine,  the  following  formula  applies  for  the  calculation 
of  the  indicated  horse-power  : — 

—  T>-    X  X'^    X  p    X  71 

4  12 

1    H.P.  ^- — 

33000 

in  which  D  =  diameter  of  cylinder  in  inches 

L  =  length  of  stroke  in  inches 

N  =  r.p.m. 

p  =  mean  effective  pressure  (lbs.  per  sq.  inch). 

n  =  no.  of  cylinders. 

For  two-cycle  single  acting  engines. 

TT  L 

— ^x—  xNx:»xw 

1  H.P.  =i 12 X  2 

33000 


310    DIESEL  ENGINES  FOR  LAND  AND  MARINE  WORK 

The  variables  upon  which  the  output  of  the  motor  depends 
are  therefore  the  diameter  of  the  cyhnder,  the  length  of 
the  stroke,  the  speed  of  revolution,  the  mean  effective  pres- 
sure and  the  number  of  cylinders.  Of  these,  the  number  of 
cylinders  and  the  speed  of  revolution  are  usually  determined 
beforehand  from  the  various  considerations,  and  the  mean 
effective  pressure  which  it  is  desirable  to  employ  in  a  Diesel 
engine  is  now  a  fairly  definite  quantity  for  the  various  types 
of  motor.  The  following  table  gives  the  values  commonly 
adopted  : — 


Table  showixg  Mean  Effective  Pressure  in  Diesel  Engines. 

Type  of  Engine. 

Lb.  per  sq.  inch. 

Four-cycle  slow  speed 

high       „          

Two-cjxle  slow       ,,          

liigh       „          

95-105 
90-100 
85-100 

70-85 

In  marine  engines  some  firms  have  a  smaller  figure  for 
continuous  oj)eration.  For  instance,  in  four-cycle  motors 
of  the  Burmeister  and  Wain  type  the  mean  effective  pressure 
allowed  is  about  90  lb.  for  marine  work  and  103-105  for  land 
motors.  The  maximum  allowable  for  this  type  of  engine  is 
about  120  lb.  per  sq.  inch.  In  the  Werkspoor  four-cycle 
engine  the  usual  mean  effective  pressure  is  95  lb.  per  sq. 
inch. 

It  is  probable,  as  more  experience  is  gained  with  the  two- 
cycle  motor,  that  a  slightly  higher  mean  effective  pressure 
will  be  allowed  for  in  the  design,  possibly  by  increasing  the 
pressure  of  the  scavenging  air  and  augmenting  the  C[uantity 
of  fuel  injected.  Naturally  an  increase  in  mean  effective 
pressure  brings  with  it  an  increase  in  the  heat  generated 
and  so  adds  to  the  difficulties  in  connexion  with  the  stresses 
in  the  cylinder  covers  and  cylinder  hners.  Even  in  recent 
designs,  pressures  as  high  as  120  lb.  per  scj^.  inch  have  been 
obtained  with  two-cycle  engines,  but  it  camiot  be  said  that 


THE  DESIGN  OF  DIESEL  ENGINES 


311 


the  result  is  satisfactory  on  the  whole,    particularly  for 
marine  work. 

Having  fixed  upon  the  speed  of  revolution  of  the  engine, 
the  length  of  stroke  is  naturally  dependent  upon  the  piston 
speed  which  it  is  permissible  to  employ  in  the  engine. 
Although  engines  are  sometimes  constructed  in  which  the 
piston  speeds  are  not  within  the  limits  given  in  the  table 
below,  it  may  be  taken  as  generally  representative  of  the 
best  practice,  and  any  variations  would  only  be  made  if 
necessitated  by  special  conditions.  It  will  be  noticed  that 
while  in  the  ordinary  four-cycle  land  engine  the  speed 
usually  adopted  is  750  to  800  feet  per  minute,  it  may  rise 
to  as  much  as  1 ,000  feet  per  minute  in  the  high-speed  engine, 
the  highest  figure  being  that  adopted  in  the  very  high-speed 
motors  employed  for  submarine  propulsion. 

Table  of  Piston  Speeds  in  Diesel  Engines. 


Piston  Speed, 

Type  of  Engine.                Land  or  Marine. 

Ft.  per  Min. 

Metres  per 
Sec. 

Foiir-cj'cle  slow  si^eed  .      Land  . 

high  ,,  .  „  .  .  . 
„            slow         ,,      .      Marine      . 

Wgh  „  .  „  .  . 
Two-cycle  slow         ,,      .      Land  or  Marine 

liigh         „      . 

750  to      800 
800  to     900 
650  to     800 
850  to  1,000 
700  to     800 
850  to  1,000 

3-75  to  4 
4       to  4-5 
3-25  to  4 
4-25  to  5 
3-5    to  4 
4-25  to  5 

It  is  probable  that  in  larger  four-cj'cle  engines  than  have 
hitherto  been  built,  say  350  B.H.P.  per  cyhnder  and 
upwards,  higher  piston  speeds  would  be  permissible,  but 
900-950  ft.  per  minute  may  be  taken  as  an  absolute 
maximum  limit  according  to  present  ideas. 

For  any  desired  indicated  horse-power  all  the  variables 
can  thus  be  determined  from  the  tables,  except  the  diameter, 
which  can  then  be  calculated.     The  length  of  the  stroke  is, 


312    DIESEL  ENGINES  FOR  LAND  AND  MARINE  WORK 

of  course,  calculated  from  the  piston  speed  from  the  equa- 
tion— 

T  _  6  S 

^~   N 

in  which  S  equals  the  piston  speed  in  feet  per  minute. 

Usually,  however,  it  is  a  definite  brake  horse-power  which 
is  aimed  for  and  not  indicated  horse-power,  which  involves 
the  question  of  the  mechanical  efficiency  of  the  motor.  In 
other  words, 

B.H.P.  =  e  X  I.H.P. 

in  which  e  equals  the  mechanical  efficiency  of  the  engine. 
The  following  table  gives  the  efficiency  usually  obtained 
with  Diesel  engines  of  ordinary  construction  of  the  various 
types  named  : — 

Mechanical  Efficiencies  of  Diesel  Engines. 


Type  of  Engine. 


Efficiency  =  e. 


Four-cycle  slow  speed 

high 
Two-cycle   slow        ,, 
high 


75-79 
69-72 
69-73 
65-70 


The  question  of  efficiency,  however,  is  apt  to  be  very  delusive, 
and  whilst  with  a  given  type  of  motor  constructed  on  usual 
lines  the  mechanical  efficiency  may  not  vary  as  much  as  | 
per  cent.,  in  some  cases  differences  of  as  high  as  10  per  cent, 
may  be  noticed  in  different  four-cycle  slow-speed  engines. 
This  is  due  mainly  to  the  manner  in  which  the  accessories 
are  driven.  The  figures  given  apply  to  what  may  be  termed 
the  ordinary  design  of  Diesel  engine  in  which  the  air  com- 
pressor for  injecting  air  and,  in  the  case  of  the  two-cycle 
engine,  the  scavenge  pump  are  driven  directly  off  the 
engine.  If,  however,  the  air  compressor  is  separately  driven, 
as,  for  instance,  in  the  case  of  some  Krupp  marine  motors 


THE  DESIGN  OF  DIESEL  ENGINES  313 

of  the  two-cycle  type,  the  efficiency  may  rise  to  about  0-78 
as  against  the  usual  0-70.  Again,  in  the  smaller  of  the 
Burmeister  and  Wain  four-cj'cle  marine  engine  only  the 
high-pressure  stage  is  driven  directly  off  the  motor,  the  low 
and  intermediate  pressure  stages  being  operated  from  another 
engine  and  the  efficiency  of  the  motor  is  as  much  as  0-84  to 
0-85.  Various  other  questions  may  compUcate  the  issue, 
such,  for  instance,  as  the  method  of  dri^^ng  auxiliary  pumps 
for  cooling  and  lubricating  oil,  as  well  (in  the  case  of  marine 
engines)  as  the  operation  of  accessory  pumps  such  as  bilge 
pumps,  etc.  When  there  are  any  marked  variations  in 
efficiency,  therefore,  these  matters  should  be  kept  well  to 
the  front,  otherwise  a  totally  erroneous  idea  of  the  actual 
efficiency  of  a  certain  motor  may  be  gained. 

Taking  all  the  factors  into  consideration,  and  assuming 
an  average  mean  pressure  and  a  mechanical  efficiency  as 
given  above,  the  output  of  a  Diesel  motor  of  the  two-cj^le 
single-acting  slow-speed  tj'pe  may  be  expressed  approxi- 
mately as 

B.H.P.  =  000014  D-  L  N  n 

As  a  matter  of  fact,  this  may  be  taken  as  a  very  fair 
figure  for  the  engines  as  at  present  constructed  of  speeds 
say  between  SO  and  150  r.p.m.,  and  for  powers  of  cOO  H.P. 
upwards.  The  actual  figure  may  vary  between  such  Umits 
as 

B.H.P.  =  0000125  D-  L  N  ?i 

and 

B.H.P.  =  0000155  D2  L  N  n 

In  four-cycle  motors  the  horse-power  is,  generally  speaking, 
represented  by 

B.H.P.  =  0  00008  D-  L  N  n 

though,  here  again,  a  substantial  deviation  is  possible. 

In  order  to  see  that  the  design  conforms  to  ordinary 
practice  various  checks  may  be  made  upon  the  dimensions 


314    DIESEL  ENGINES  FOR  LAND  AND  MARINE  WORK 

obtained  in  the  manner  given  above.  The  ratio  of  stroke 
to  bore  in  various  types  of  Diesel  engines  is  fairly  definite, 
although  there  are  marked  deviations  among  different  firms 
according  to  their  peculiarities  in  design.  In  fact,  the 
actual  ratio  varies  from  unity  to  just  over  2,  as  will  be  seen 
from  the  tabulated  list  of  dimensions  of  various  engines 
given  later.  The  last-mentioned  figure  is,  however,  an 
exception,  whilst  the  ratio  of  unity  is  that  which  is  adopted 
on  very  high-speed  engines,  such  as  those  of  the  submarine 
type,  for  obvious  reasons,  since  it  is  necessary  to  keep  down 
the  piston  speed  to  a  reasonable  amount. 

For  four-cycle  slow-speed  engines  of  the  ordinary  sta- 
tionary type,  where  practice  has  become  much  more  stan- 
dardized than  with  other  motors,  the  usual  ratio  of  stroke 
to  bore  which  is  adopted  is  1-4  to  1-5,  whilst  in  the  case  of 
very  high-speed  motors,  say  those  running  at  350  r.p.m. 
and  above,  the  ratio  hardly  varies  from  between  unity  to 
1-1,  according  to  the  speed  and  power  of  the  motor. 
For  two-cycle  slow-speed  engines,  particularly  those  of 
the  marine  type,  1-4  to  1-5  is  quite  a  common  figure, 
although  many  engines  have  the  ratio  1-8  to  1-9  and 
even  above. 

Although  there  is  no  absolute  line  of  demarcation  Diesel 
engines  are  generally  divided  into  two  classes,  known  as  the 
high-speed  and  slow-speed  type.  The  average  figures  are 
given  in  the  following  table  : — 

Speeds  of  Rotation  of  Diesel  Engines. 


Type  of 

Engine. 

Land  or  Marine. 

Revs,  per  Minute. 

Four-cycle  slow 

sjieed    . 

Land 

140-190 

high 

,,         ... 

200-400 

, ,            slow 

Marine   . 

100-160 

high 

11          ... 

300-500 

Two-cycle  slow 

Land  or  Marine 

90-150 

liigb 

" 

300-450 

THE  DESIGN   OF  DIESEL  ENGINES 


315 


The  volume  swept  throiigli  by  the  piston  of  a  Diesel 
engine  per  B.H.P.  per  minute  is  a  fairly  constant  quantity 
for  a  particular  type  of  engine,  and  this  fact  may  be  used 
as  a  check  upon  the  values  which  are  obtained  for  the 
stroke  and  bore  of  a  motor,  by  the  rules  and  formulae 
given  previously.  The  table  below  gives  a  fair  idea  of  the 
various  volumes  for  the  different  type  of  engines,  al- 
though the  figures  are  naturally  dependent  upon  several 
varying  factors,  and  above  all  upon  the  mean  effective 
pressure  which  is  employed  in  the  motor.  It  may  be  taken 
that  the  ordinary  engine  will  come  within  the  limits  given 
in  the  table  unless  there  are  some  exceptional  conditions 
imposed. 

Piston  Volume  swept  through  per  B.H.P.  in  Various  Engines. 


Type  of  Engine. 

Piston  Volume  swept  through  per  B.H.P. 

Cubic  Metres  per 
Min. 

Cubic  ft.  per  Min. 

Foiir-cycle  slow  speed 

high       ,.          .      . 

Two-cycle   slow       ,,          .      . 
high       „          .      . 

0-34  to  0-38 
0-30  to  0-38 
0-17  to  0-20 
0-18  to  0-22 

120  to   134 
106  to   134 

60  to     70 

03  to      77 

As  was  stated  earlier  in  the  volume  (see  page  23)  the 
clearance  space  in  an  ordinary  Diesel  motor  of  the  four- 
cycle slow-speed  type  is  so  designed  that  the  volume  is 
approximately  one-fifteenth  of  the  volume  swept  through 
by  the  piston.  This  may  of  course  be  varied,  depending 
on  the  maximum  pressure  of  compression  which  takes  place 
within  the  cylinder,  and  moreover  the  fact  must  be  remem- 
bered that  in  general  the  piston  is  dished,  so  that  there  is 
less  than  one-fifteenth  of  the  length  of  the  stroke  between 
the  top  of  the  piston  and  the  bottom  of  the  cylinder  cover 
at  the  sides.  The  clearance  volume  may  be  calculated  by 
following  out  the  law  of  the  compression  of  the  air  durmg 


316    DIESEL  ENGINES  FOR  LAND  AND  MARINE  WORK 

the  compression  of  the  stroke.     From  the  ordinary  formulae, 
the  following  equation  as  usual  holds  good  : — 

Referring  to  Fig.  6,  page  21,  it  will  be  seen  that 

Va  =  clearance  volume 

Vi  =  clearance  volume  +  V^ 

where  V^  =  volume  swept  through  by  piston 

Pi  =  Pressure  before  compression 
Pa  =  Pressure  after  compression 

In  another  form 

P3  y-  =p,  (V.  +  V,)  « 
/Va  +  Va«      p. 


or  log  ^'  =71  log  (1   +  „'^) 


Pi  ^  V         V 

In  general  n  =  1-25  to  1-3  say  1-25 

P  /500\ 

Taking  the  ratio  — ^  =  31  as  an  example  ( y^J 


we  have  1-25  log  M    +  ^j  =  log  31 

or  log  (1   +  — ^j  - 


yj        1-25 


=  M933 
=  log  16 

V 

Or    -lii  =  15 


THE  DESIGN  OF  DIESEL  ENGINES 


317 


10 

00-too      oooooooc-.r35ao"      "••           "^      icm-mo'-o      >o«« 
-t<-tcO'^-iio-<MW-+f.t;-       0           Mococ-coocs'TiO       '^'-r'?       ^}^} 

02 

0  0  C'  >ra  10  'o  0  O!  c  0  -f  0  c  ic  "f:  ic  0  "C  ■>)  C5  c  03  s  00  0  >o  —  10  —  >c  —  — ' 
eo  05  ;r  t^  CI  00  —  00  r^  —  01  c-i  -c  -^  00  — 1  00  -x  'M  w  "M  T)<  — 1  00  —  — '  -t  0  1-  >~  00  M 

J3CC 

C 

eiioin           -f           >ot^„in           >^           t^ioio           0010               io>n 

Stroke. 

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cc  tc  t^  -f  -*  m  -+  (^  00  —  ©  35  CO  fc  cc  -+  q_  — _^  c:  -^  00  -M^^  'O  00  -f  "O  cc  -M  CO  c<5  --o 

Boro 
mm.      ' 

3lliiiSliiiiiiiilsii?liiSISiSii5 

f4 

- 

PM 

oooooiooooocooooo^coccoooooooooooo 

^^^^                                                 -f  r^  r^            -Tim'                                                                             « 

a. 

IV 

1    .   .   .1    .   .   J    .   .   .   .1    .   .   .1    .   .    :    :    .    .    .   .1    :   =   .   . 

1    :   :   :;.St  —   rj    r   :;   1   :.£."=  ::   :;   r^    :.   ^   ^   :.   i   i   :   :;-^'^'  r   :   —  0 
c             0             0                 '^            s.                              ^                —  •- 

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J                             1                                 ^1 

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.    -  g-:?;  .  s  .  -  ^  -  s-*^  -^  j-  ■'^  »  r  S-   ^  *  ^  i  ^  0 .5  S-^ 

318    DIESEL  ENGINES  FOR  LAND  AND  MARINE  WORK 


Crank  Shafts. — Making  allowances  for  the  special  char- 
acteristics of  the  engine,  the  diameter  of  the  crank  shaft 
for  a  Diesel  motor  can  be  calculated  ab  initio  from  the  known 
rules  which  are  applied  in  steam  engine  practice.  The 
calculations  are  based  on  the  equivalent  twisting  moment, 
deduced  from  the  combination  of  the  twisting  and  bending 
moment  of  the  crank  shaft,  considering  the  shaft  as  a  beam 
supported  from  two  fixed  points,  namely  the  centres  of  two 
adjacent  bearings. 

As,  however,  the  maximum  pressure  exerted  on  the 
pistons  in  Diesel  engines  is  fairly  constant,  and  as  the  dis- 
tance between  the  bearings  generally  has  a  definite  relation 
to  the  diameter  and  stroke  of  the  cylinder,  it  is  possible 
to  obtain  a  simple  and  accurate  formula  for  a  crank  shaft 
diameter  in  terms  of  the  diameter  and  stroke  of  the  cylinder. 
In  the  formula  given  below  the  assumption  has  been  made 
that  the  distance  between  the  centre  of  two  adjacent  bear- 
ings is  approximately  1-3  times  the  stroke  of  the  engine, 
and  about  twice  the  diameter  of  the  cylinder.  Even,  how- 
ever, when  this  is  not  correct  the  formula  holds  true  within 
a  very  close  margin. 

If  D  =  diameter  of  cylinder  in  inches 
L  =  stroke  of  piston      ,,  ,, 

d  =  diameter  of  crank  shaft  ,, 
then  d  =  K^B^i, 
where  K  =  a  constant. 

The  value  of  K  is  given  in  the  following  table  for  various 
types  of  engines. 

Table  of  Constants  for  Determination  of  Crank  Shaft 
Diameter. 


Number  of  Cylinders. 


Four-cycle  Engine. 


6  or  under 


Two-cycle  Single 
Acting. 

3 

4 
() 
8 


Two-cycle  Double 
Acting. 


Constant 
K. 


•525 
•53 
•539 
•555 


THE  DESIGN  OF  DIESEL   ENGINES  319 

The  diameter  of  the  crank  shaft  in  a  Diesel  engine  varies 
from  0-55  to  0-65  of  the  cylinder  diameter,  the  former  figure 
being  common  in  ordinary  four-cycle  land  engines  of  the 
slow-speed  type,  increasing  to  about  0-58  for  high-speed 
four-cycle  engines,  to  0-6  for  four-cycle  marine  engines  and 
0-62  up  to  0-65  for  two-cycle  marine  engines  in  which,  how- 
ever, the  margin  of  safety  appears  to  be  somewhat  large. 

For  marine  engines,  although  no  regulations  have  yet 
been  issued  by  Lloyd's,  the  Germanischer  Lloyd  have 
published  the  following  rules  for  the  calculation  of  crank 
shafts.  The  result,  however,  gives  practically  the  same 
figure  in  every  case  as  that  when  applying  the  formulae 
given  above. 

The  rule  is  that  the  diameter  of  the  shaft  shall  be  cal- 
culated from  the  following  formula  : — 

d  =  n/D^IT 

in  which  d  =  the  diameter  of  the  crank  shaft  in  centimetres. 

D  =  cylinder  diameter  in  centimetres. 

A  =  a  constant  determined  from  the  following  table. 

H  =  stroke  of  piston  in  centimetres. 

L  =  distance  between  the  centres  of  two  adjacent  bear- 
ings in  centimetres. 

No.  of  Cvliiiders.  A. 


1,  2,  and  3 0-09H  +  0-035L 

4 0-lOH  +  0-035L 

5 0-llH  +  0-035L 

6 013H  +  0035L 


The  above  table  applies  only  to  two-cycle  single-acting 
engines.  For  four-cycle  engines  the  number  of  cylinders 
in  the  engine  should  be  divided  by  two  when  arriving  at  the 
constants  given  above. 

For  two-cycle  double-acting  engines  the  number  of  cylin- 
ders in  the  engine  should  be  multiplied  by  two  in  order  to 
arrive  at  the  constants. 


320    DIESEL  ENGINES  FOR  LAND  AND  MARINE  WORK 

In  determining  the  diameter  of  the  crank  shaft  by  the 
above-mentioned  rules  the  maximum  stress  which  is  allowed 
is  about  7,500  lb.  per  sq.  inch. 

The  crank  pin  is  almost  invariably  made  of  the  same 
diameter  as  that  of  the  crank  shaft.  The  length  of  the 
crank  pin  is  kept  as  low  as  possible,  being  generally  about 
1  -3  times  the  diameter  of  the  crank  pin  and  often  below  this 
figure.  The  length  of  the  journal  is  also  kept  within  reason- 
able limits,  and  the  bearing  pressure  on  the  crosshead  pin 
and  the  crank  pin  bearing  is  not  allowed  to  exceed  2,000  lb. 
per  sq.  inch,  although  this  figure  is  quite  a  common  one 
in  modern  Diesel  engine  practice. 

In  those  engines  in  which  the  compression  pressure  in  the 
cylinder  is  kept  down  to  a  figure  below  that  ordinarily 
adopted,  for  instance  in  the  case  of  Werkspoor  motor,  a 
correspondingly  diminishing  pressure  on  the  crank  pin  is 
allowed  for,  and  its  diameter  is  made  about  5  per  cent, 
less  than  that  actually  calculated  from  the  formula  given 
above.  The  practice,  however,  is  hardly  one  to  be  gener- 
ally recommended  in  view  of  the  uncertainty  as  to  the  exact 
pressures  which  come  on  the  crank  shaft. 

The  rules  given  above  for  the  calculation  of  the  diameter 
of  the  crank  shafts  are  those  for  ordinary  Diesel  engines 
in  which  the  air  compressor  for  injection  and  starting  air 
is  driven  diiectly  off  the  engine.  If  this  compressor,  how- 
ever, is  separately  driven,  as  is  sometimes  the  case  with  large 
marine  installations,  a  very  slight  allowance,  say  about  5 
percent.,  of  the  diameter  may  be  deducted  from  the  figures 
obtained  from  same  by  the  rules  given. 

Having  obtained  the  diameter  of  the  crank  shaft,  the 
cranks  may  be  designed  from  the  ordinary  known  rule  which 
applies  equally  in  the  case  of  a  steam  engine.  With  marine 
engines  in  calculating  the  diameter  of  the  tunnel  shaft  the 
same  relations  between  this  and  the  diameter  of  the  crank 
shaft  holds  as  is  applied  in  steam  engines,  namely  that  the 
diameter  of  the  tunnel  shaft  is  about  5  per  cent,  less  than 
that  of  the  crank  shaft. 

In  most  Diesel  engines  of    the  ordinary  four-cycle  land 


THE  DESIGN  OF  DIESEL  ENGINES 


321 


type,  with  trunk  pistons  the  length  of  the  connecting  rod 
is  approximately  2|  times  that  of  the  stroke  of  the  pis- 
tons, but  as  a  rule  this  is  diminished  when  crossheads  are 
employed.  In  many  four-cycle  marine  engines  of  large 
size  the  length  of  the  connecting  rod  is  twice  that  of  the 
stroke,  whilst  in  two-cycle  and  marine  engines  the  figure  is 
about  21  times. 

For  large  engines,  particularly  for  marine  work,  it  is 
desirable  to  have  built  up  crank  shafts,  and  this  is  one  of  the 
reasons  for  the  employment  of  a  fairly  long  stroke  in  engines 
of  this  type. 

SizK  OF  Craxk   Shafts. 
(All  dimensions  are  in  millimetres.) 


'J'vi)e 

of 

Engine. 

Fovu- 

or 
Two 
Cycle. 

B.H.P. 

No. 
of 
Cylin- 
ders. 

Dia. 

Stroke 

R.P.M. 

Crank 

Shaft 

dia. 

(Jrank 
Pin 
dia. 

Ratio  of 
Crank 
Sliaft  to 
cylinder 
dia. 

]\rup])  . 

4-cycle 
land 

300 

4 

380 

450 

300 

220 

220 

•58 

Werks- 

4-cycle 

GOO 

4 

500 

640 

215 

270 

280 

•54 

poor 
Carels  . 

land 

4-cycle 

land 

700 

4 

570 

780 

150 

320 

325 

•56 

Werks- 

4-cycle 

1,100 

6 

560 

1,000 

125 

340 

340 

•60 

poor 
Schnei- 

marine 
2 -cycle 

900 

4 

450 

560 

230 

260 

260 

•58 

der 

marine 

Tecklen- 

2-cycle 

1,500 

6 

510 

920 

120 

330 

330 

•64 

borg 

marine 

Reiher- 

2-cycle 

1,800 

G 

600  1,100 

90-100 

390 

400 

•65 

stieg 

marine 

Air  Compressors. — In  view  of  what  has  already  been 
said  in  regard  to  the  diflliculties  that  exist  in  comiexion 
with  the  exact  determination  of  the  cylinder  dimensions 
of  a  Diesel  engine,  it  will  readily  be  understood  that  the 
calculations   relating   to   air   compressors   are   even   more 

Y 


322    DIESEL  ENGINES  FOR  LAND  AND  MARINE  WORK 

subject  to  variation.  The  exact  quantity  of  air  required 
for  injection  has  not  been  accurately  determined  ;  more- 
over, since  it  varies  with  different  fuels,  and  the  compressor 
has  also  to  provide  air  for  starting  purposes,  most  builders 
prefer  to  allow  an  ample  margin  in  the  design. 

In  four-cycle  slow-speed  stationary  practice  the  many 
years'  experience  in  operation  which  has  been  gained  enables 
this  margin  to  be  reduced  nearly  to  the  minimum  limit, 
but  even  in  this  case,  in  any  design  which  is  a  departure 
from  the  standard,  a  reasonable  excess  should  be  allowed. 
With  high-speed  four-cycle  engines,  however,  the  same 
knowledge  has  not  yet  been  obtained  and  the  variations  in 
different  designs  are  more  marked,  whilst  as  regards  two- 
cycle  motors  there  is  little  doubt  that  in  most  cases  the 
capacity  of  the  compressor  has  been  considerably  in  excess 
of  actual  requirements. 

At  sea  it  is  of  course  especially  important  that  there 
should  be  no  lack  of  compressed  air,  since  not  only  is  it 
used  for  other  purposes  besides  injection  and  starting,  such 
as  the  operation  of  servo  motors  for  reversing,  etc.,  and  for 
certain  auxiharies,  but  tlie  demands  for  manoeuvring  are 
at  times  excessive.  This  is  to  a  certain  extent  counteracted 
by  the  fact  that  an  auxiliary  compressor  driven  by  an  inde- 
pendent engine  is  practically  invariably  installed,  which  is 
put  into  operation  if  the  pressure  in  the  receivers  falls, 
and  when  much  manoeuvring  is  required,  as,  for  instance, 
when  in  a  river  or  harbour.  It  is  undoubtedly  preferable 
that  an  air  compressor  should  be  over  designed  than  that 
it  should  scarcely  be  capable  of  its  normal  work,  but  the 
desire  for  safety  has  certainly  been  carried  too  far  in 
some  cases.  For  instance,  it  is  probably  sufficient  to  design 
the  compressor  for  a  two-cycle  marine  engine  with  an  output 
of  6  litres  (-21  cub.  foot)  per  B.H.P.  per  min.  of  the  main 
engine,  whereas  in  some  cases  as  much  as  10  or  12  litres  per 
B.H.P.  per  min.  has  been  allowed. 

In  one  of  the  most  usual  type  of  compressor  constructed 
which  is  of  the  vertical  design,  driven  off  one  end  of  the 
engine  directly  from  the  crank  shaft,  it  is  not  difficult  to 


THE  DESIGN  OF  DIESEL  ENGINES 


323 


increase  the  deKvery  volume  of  air  should  tests  show  that 
it  is  insufficient.  This  can  be  carried  out  merely  by  the 
replacement  of  the  connecting  rod  by  a  shorter  one  so  as 
to  increase  the  length  of  the  stroke  of  the  compressor  and 
thus  increase  the  volume  of  air  compressed.  Naturally 
this  "  trial  and  error  "  method  is  not  to  be  recommended 
and  in  any  case  would  only  have  to  be  adopted  on  an  abso- 
lutely new  design. 

The  following  table  gives  some  data  regarding  the  usual 
capacities  of  compressors  for  various  types  of  engine,  the 
volumes  being  based  on  the  air  entering  the  low-pressure 
stage  of  the  machine.  It  is  usual  to  express  the  amount 
of  air  in  terms  of  the  ratio  of  volume  swept  througli  by  the 
piston  of  the  low-pressure  stage  of  the  compressor  to  that 
by  the  pistons  of  the  working  cylinders — that  is  to  say  by 
as  man}'  pistons  as  there  are  cylinders. 


Table  of  Capacities  of  Air  Compressors. 


Type  of  Engine. 


Capacity  of  Compressor. 


Litres  per       Cub.  ft.  per 

B.H.P.  per      B.H.P.  per 

Min.  Mint. 


Volume 
Ratio  of 
Compressor  to 
AVorking 
Cylinders 
per  cent. 


Four-cycle  slow  sjieed 

6  to    9 

•21  to -31 

5-5  to    7 

high      „          .      . 

8  to  10 

•28  to  •So 

9      to    8 

Two-cj'cle   slow      ,,          .      . 

6  to    9 

•21  to  •SI 

6     to  12 

high      „          .      . 

9  to  12 

•31  to^42 

10     to  14 

In  reversible  compressors  of  the  marine  type  some  de- 
signers allow  an  extra  capacity  of  10  or  12  per  cent,  above 
that  for  the  non-reversible  motors,  but  this  is  by  no  means 
general. 

In  many  respects  it  is  not  advantageous  to  design  a  com- 
pressor in  excess  of  requirements  since  in  this  case  air 
has  to  be  discharged  from  the  delivery  of  the  first  stage  or 
else  the  suction  has  to  be  throttled.  This  means  that  the 
ratio  of  compression  in  the  H.P.  stage  is  too  high  (it  should 


324    DIESEL  ENGINES  FOR  LAND  AND  MARINE  WORK 

not  exceed  9  to  1 )  and  too  much  work  is  pnt  upon  the  H.P. 
stage.  On  the  whole  it  may  be  said  that  the  lower  limits 
of  the  figures  given  in  the  above  table  represent  the  best 
practice. 

Design  of  Air  Compressors. — Air  compressors  for 
Diesel  engines  are  designed  to  deliver  air  from  the  high- 
pressure  stage  at  from  CO  to  70  atmospheres,  or  from  COO 
to  1 ,000  lb.  per  sq.  inch.  It  is  obviously  impossible  to  employ 
single-stage  compressors  for  this  work  owing  to  the  fact 
that  the  temperature  of  the  air  after  compression  would 
be  excessive.  Machines  of  the  two-stage  type  are  gener- 
ally utilized  for  the  smaller  sizes  of  engine,  and  as  the  diminu- 
tion in  the  number  of  stages  reduces  the  complication, 
two-stage  compression  has  much  to  recommend  it.  For 
engines  up  to  500  B.H.P.  it  appears  quite  suitable,  but 
above  this  power  it  is  common  to  adopt  three-stage  com- 
pression. With  some  types  of  compressors,  however,  such 
as  the  Reavell  quadruplex  machine,  it  is  convenient  to 
employ  more  than  two  stages  in  any  case,  so  that  even  with 
the  smiall  engine  when  this  type  of  compressor  is  employed 
three-stage  compression  is  adopted.  Inter-cooling  and 
after-cooling  are,  of  course,  necessary  with  all  types  of  com- 
pressors in  order  to  keep  the  temperature  of  the  air  down 
to  a  moderate  figure. 

The  pressure  for  the  stages  are  obtained  in  the  following 
manner,  in  a  two-stage  compressor — 

If  P  =  Final  compression  pressure  (absolute)  in  lb.  per 

sq.  inch, 
Pi  =  Pressure    (absolute)    at  end  of  first    stage  in  lb. 
per  sq.  inch, 

then  Pi  =  V  P  X  14-7 

taking  atmospheric  pressure  as  14-7  lb.  per  sq.  inch.  If 
the  pressure  be  expressed  in  the  Continental  system  in 
atmospheres  then 

Px=Vp 


THE   DESTGX   OF   DIESEL   ENGINES  .325 

In  a  three-stage  compressor  if  P^,  =  pressure  in  11).  per 
sq.  inch  at  end  of  second  stage, 

^     14-7 


^V 


3/14-7 
P 
or  if  the  pressure  again  be  expressed  in  atmospheres, 

Pi  =  </P 

P„    =  </p2 

From  the  tables  given  previously  the  approximate  capa- 
city of  the  compressor  in  terms  of  volume  of  air  delivered 
by  the  low-pressure  stage  can  be  obtained.  This  gives  the 
volume  swept  through  by  the  low-pressure  piston  of  the 
compressor,  the  stroke  and  bore  of  which  can  then  be 
determined.  The  actual  ratio  of  the  stroke  to  the  bore 
depends  a  good  deal  upon  individual  preference,  for  there 
is  a  wide  margin  allowable  in  the  piston  speed  of  a  ccm- 
pressor.  In  most  ordinary  four-cycle  engines  of  the  slow- 
speed  type  it  varies  between  0-75  and  1  -2  metres  per  second, 
or  150  to  230  feet  per  minute.  In  high-speed  motors  it  is 
frequently  2  to  2-5  metres  per  second,  or  about  400  to  TOO 
feet  per  minute,  and  this  figure  may  also  be  attained  in 
large  two-cycle  engines,  in  which,  although  the  speed  of 
revolution  is  low,  the  stroke  has  to  be  made  of  a  reasonable 
length  for  general  convenience. 

Taking  the  case  of  a  two-stage  compressor,  the  diameter 
of  the  two  cylinders  can  be  obtained  as  follows  : — 

Let  V       =  Vol.  of  L.P.  cylinder  as  obtained  from  table 
above. 
D  =  diameter  of  L.P.  cylinder 
T>i=       ,,  ,,    H.P.        ,, 

S  =  stroke  of  piston  of  compressor 
P,  P„,Pi=the    pressures    (absolute)    at    the    beginning 
of  the  L.P.  stage,  the  eni  of  the  L.P.  stage, 
and  the  end  of  the  H.P.  stage  respectively. 


326    DIESEL  ENGINES  FOR  LAND  AND  MARINE  WORK 


V„,  Yi  =  Volumes  of  air  at  the  end  of  first  stage  and 
second  stage  compression  respectively, 

V„^  =  Volume  of  air  after  intercooling  between  first 

and  second  stage. 

7]- 

=      Di-iS  omitting  clearance  and  losses.  .  .  .(1) 

From  reference  to  Fig.  166  it  will  be  seen  that  the  action 
Pa  RVJ, 


PaVaTa 


Pa  ]mk 
Atmospheric  Line 


.PV.T 


Volume      "^ 

Fig.   IGG. — Compression  Curves  in  Two-Stage  Compressor. 

of  the  compressor  is  to  comjtress  according  to  the  equation 
P  V  =  constant  from  conditions  P,  V,  T,  to  conditions 
Pa,  V„,  T,,  ;  next  to  cool  the  gas  till  conditions  P„,  V^S 
T„i,  are  reached,  and  then  compress  to  conditions  Pi,  Vi, 
Ti.     The  value  of  n  is  as  follows  : — 

For  adiabatic  expansion     n  =1-41 

,,     isothermal         ,,  n  =  1-00 

In  general  practice  n  =1-25 


THE  DESIGN   OF  DIESEL  ENGINES  327 

To  determine  V„^  which  is  first  necessary,  proceed  as 
foUows  : — 

PV«  =P„  V/    (2) 

V  is  known,  P  =  l-i-T  lb.  per  sq.    inch,  and   P„   can  be 

determined  from  formulae  given  above,  whilst  n  may  be 

taken  as  1-25,  hence 

P  V" 
V/=-y       (3) 

from  which  V„  can  be  determined. 

After  cooling  the  compressed  gas  (P„,  V„,  T„)  in  the 
intercooler,  its  temperature  becomes  T/  and  the  volume 
is  reduced  to  V„^. 

From  page  11  equation  (2) 

T        /P  \*t=l 

T?=(i?)"        W 

since  in  this  case  y  is  replaced  by  n 

/   P  \^^  /  P    \''^ 

°'^"=(i4:7)      ^^  =  (i4^)     ^'^  ^'^ 

T  may  be  taken  as  520°  F.  or  288'  C.  absolute,  hence  T„ 
is  then  known. 

We  may  now  obtain  V,/  since  the  pressure  P„  is  constant 
during  the  cooling. 

y  1       ^  1 

1^=±±      (6) 

V         T 

The  temperature  T^^  to  which  the  air  is  cooled  will  be 
about  CO"  F..  or  say  32°  C.  Temperature  must  of  course 
be  absolute,  the.cfore  T„i  =  460  +  90  =  550 

V   T  1 

hence  ^  </  =     "     "    can  be  determined     (7) 

From  the  above 

4  V  1                      /4  V 
D/—    -"r   ov  J)^^y^      (8) 

which  gives  the  value  of  the  diameter  of  the  H.P.  stage  of 


328    DIESEL  ENGINES  FOK  LAND  AND  MARINE  WORK 

the  compressor.     The  L.P.   stage  diameter  is  then  found 
from 


V  =-(D2  -Di2)  X  S 
4 


or      D  = 


4V 


X  Di2 


.(9) 
(10) 


The  calculations  may  be  made  clearer  by  working  out  an 


YZZUUZLk 


■^^;^ssssss: 


//////// 


Fig.   167. — Diagrammatic  Eeprcscntation  of  Two-Stage  Compressor. 

example,  takirg  a  four-cj'cle  high-speed  engine  capable  of 
developing  275  B.H.P.  at  300  r.p.m.,  having  three  cylin- 
ders, bore  15  inches,  stroke  17|  inches.  For  this  the 
capacity   of    the   compressor   may   be   taken    as    9   litres, 


THE  DESTDN   OF  DIESEL  ENGINES  329 

or  say  -SO  cub.  foot  per  B.H.P.  per  min.  The  com- 
pressor is  designed  for  an  absolute  pressure  of  1,000  lb. 
per  sq.  inch,  hence  the  absolute  pressure  at  the  end  of  the 
first  stage  is 


P^  =  v^U-T  X  1000  =121-1  lb.  per  sq.  inch 
or  =  106-4  lb.  per  sq.  inch  gauge. 

Taking  the  piston  speed  of  the  compressor  as  425  feet 

per  min.   the  stroke  S      =     =  8A  inches. 

^  300  X  2  ^ 

The  volume  swept  through  by  the  piston  of  the  L.P. 
cylinder  is 

„       -30  X  275        ^^^       1,    r     ^ 

V  = =  -275  cub.  foot 

300 

=  486  cub.  inches. 
From  equation    (3) 


V 

1-25 
a 

14-7                 1-^ 
-              X  486 
1211 

hence  V, 

,  =  89-2  i 

cub. 

inches. 

From 

equation 

(5) 

T„^ 

=  C^'i)"-^   X  520 
=  788°  F.  absolute. 

From 

equation 

(") 

^  _  89-2  X  550 

"                788 

=  62-5  cub.  inches. 
From  (8)  the  diameter  of  the  H.P.  cylinder  is 


=    3  06,  say  3  inches. 


330    DIESEL  ENGINES  FOR  LAND  AND  MARINE  WORK 

To  determine  the  diameter  of  the  L.P.  cyhnder  use  equa- 
tion (H)  from  which 


TT   X  8-5 
=  9-05  say  9  inches. 

The  compressor  would  therefore  be  made  with  a  stroke 
of  8|  inches,  the  diameter  of  the  H.P.  cyhnder  being  3 
inches  and  of  the  L.P.  cyhnder  9  inches. 

Scavenging  Pumps. — The  question  of  scavenging  in 
two-cycle  Diesel  engines  has  an  important  influence  upon 
the  design,  an  influence  which  will  become  more  and  more 
marked  with  the  development  of  the  larger  type  of  engine 
particularly  for  marine  work.  Whilst,  as  explained  previ- 
ously, the  port  scavenging  engine  has  enormous  advantages, 
in  the  matter  of  simplicitj^,  and  reducing  the  risks  of  cracks 
in  the  cyhnder  cover  to  a  minimum,  the  design  of  engines 
employing  this  method  is  naturally  not  ^\dthout  its  own 
difficulties.  In  order  to  bring  these  out  more  clearly  refer- 
ence may  be  made  to  Figs.  168  and  169,  which  illustrate 
the  cycles  of  the  valve  and  port  scavenging  engine  re- 
spectively. 

Follomng  the  indicator  diagram  in  Fig.  168  fuel  injection 
commences  at  c  and  continues  at  more  or  less  constant 
pressure  to  h  when  the  supply  is  cut  off  and  expansion  pro- 
ceeds along  the  line  h,  a,  until  at  a  the  exhaust  ports  are 
uncovered  by  the  piston  in  its  outward  stroke.  From  a  to 
e  the  pressure  drops  rapidly,  reaching  approximately  atmo- 
spheric at  e  when  the  scavenge  valve  in  the  cylinder  cover 
opens,  and  the  cylinder  is  filled  with  scavenging  air  along 
ef  and  then  back  along  /e,  the  scavenging  valve  closing 
approximately  at  the  same  time  (usually  just  before)  as 
the  exhaust  ports  are  covered.  Compression  then  follows 
from  d  to  c  and  the  cycle  recommences. 

It  will  therefore  be  seen  from  this  diagram  that  what  may 
be  termed  the  useful  stroke  is  from  m  to  d  or  x,  whilst 
the  total  stroke   is  represented   by  mf  or  y.     In  ordinary 


Fig.   1G8. — Diesel  Engine  Indicator  Diagram  with  Valve     Scavenging.] 

331 


^^abaat    yi 


r?i/ 


Fig     169.  — Diagram  of  Engine  with  Port  Scavengi 
332 


mg. 


THE  DESIGN  OF  DIESEL  ENGINES  333 

engines,  up  to  say  300  or  400  B.H.P.  per  cylinder,  this 
ratio  with  valve  scavenging  at  the  motors  is  about  0-8, 
although  it  decreases  in  larger  motors. 

Turning  now  to  Fig.  169,  which  represents  an  engine  in 
which  port  scavenging  is  adopted,  as  before  fuel  is  injected 
at  c  and  combustion  takes  place  along  cb,  expansion  follow- 
ing along  ha  down  to  a  ;  the  piston  then  uncovers  the  exhaust 
ports  and  allows  the  pressure  of  the  exhaust  gases  to  drop 
until  e,  when  the  scavenging  air  enters  through  the  ports  in 
the  other  half  of  the  cylinder  now  being  uncovered  by  the 
piston.  In  order  to  avoid  any  back  pressure  and  conse- 
quent flowing  back  of  the  exhaust  gases  into  the  scavenge 
pipe  it  is  necessary  that  the  pressure"  of  the  exhaust  gases 
should  drop  in  this  way,  although  it  is  found  that  the 
scavenge  ports  may  open  whilst  the  pressure  in  the  cylinder 
is  still  about  2  lb.  per  sq.  inch  above  atmospheric.  From 
e  to  /  and  back  again  from  /  to  e  the  cylinder  is  being  charged 
with  scavenging  air,  but  on  the  return  stroke  at  e  the 
scavenge  ports  are  once  more  closed,  the  exhaust  ports 
remaining  open  until  d,  when  compression  commences  and 
takes  place  as  before  along  the  line  db. 

In  this  case  it  will  be  seen  that  the  effective  length  of  the 
stroke  is  again  md  or  x  and  the  whole  stroke  y,  but  it  is 
apparent  from  the  diagram  that  the  ratio  of  x  to  y  must 
be  very  much  less  than  before,  and  in  fact  even  in  moderate 
size  engines  is  between  -7  and  -72.  In  larger  engines  this 
figure  is  decreased. 

It  is  quite  obvious  in  engines  employing  port  scavenging, 
since  half  the  belt  of  the  cylinder  at  the  bottom  has  to  be 
occupied  with  the  ports  for  the  inlet  of  the  air,  and  only  the 
other  half  for  the  exhaust  ports,  that  the  latter  must  be 
considerably  longer  in  the  port  scavenging  engine  than  with 
valve  scavenging.  The  action  of  the  port  scavenging  engine 
as  described  is  that  of  one  in  which  one  set  of  ports  only 
are  employed,  but  it  can  readily  be  seen  that  if  more  scaveng- 
ing air  can  be  pumped  into  the  cylinder  after  the  exhaust 
ports  have  closed  an  advantage  will  accrue.  This  is  the 
method  which  has  been  adopted  in  the  Sulzer  engine  and 


334  DIESEL  ENGINES  FOR  LAND  AND  MARINE  WORK 

in  other  t^^pes,  but  this  lias  no  effect  on  the  length  of  the 
exhaust  ports. 

The  calculation  of  the  dimensions  of  the  exhaust  and 
scavenging  ports  in  a  Diesel  engine  of  this  type  is  too 
involved  to  be  based  on  theoretical  consideration  entirely 
since  the  size  is  dependent  upon  many  factors  which  cannot 
be  accurately  calculated,  being  themselves  in  many  cases 
inter-dependent.  With  a  scavenging  air  pressure  of  from 
3  to  5  lb.  per  sq.  inch  above  atmosphere,  the  usual  velocity 
of  the  scavenging  air  is  somewhe.e  in  the  neighbourhood 
of  320  to  350  feet  per  minute.  The  scavenging  pump  for 
a  port  scavenging  engine  should  be  capable  of  delivering 
from  1-5  to  two  times  the  volume  of  the  cylinder  vdih  an 
allowance  of  about  1  -3  to  1  -5  times  the  cj^uantity  of  scaveng- 
ing air  entering  the  cylinder  as  compared  with  the  actual 
volume  displacement  of  the  piston. 

There  should  usually  be  7  to  8  ports  both  for  the  admis- 
sion of  scavenge  air  and  the  exit  of  the  exhaust  gases,  and 
the  combined  width  of  these  i?  in  a  neighbourhood  of  -45  to 
•55  times  the  cyhnder's  circumference,  being  equally  divided 
between  the  scavenge  ports  and  exhaust  ports.  In  other 
words  the  total  width  of  the  scavenging  port  should  be  from 
•225  to  ^275  of  the  periphery  of  the  cylinder. 

The  length  of  the  exhaust  port  in  a  vertical  direction 
mth  plain  port  scavenging,  is  between  2  and  2-2  times  the 
vertical  length  of  the  scavenging  port. 

The  following  formula  for  the  dimensions  of  the  exhaust 
and  scavenging  ports  "wdll  be  found  fairly  accurate,  although 
they  are  in  general  somewhat  on  the  small  side. 


A  =  •0065  S  3  V  D%2 

B  =  -00 L3  S  3  ^  B^n'- 

where  A  =  Length  of  inlet  port  in  inches 

B  =  Length  of  exhaust  port  in  inches 
D  =  Diameter  of  cyhnder  in  inches 
n  —  revolutions  per  minute 
S  =  Stroke  of  piston  in  inches. 


THE  DESIGN  OF  DIESEL   ENGINES  335 

This  presupposes  the  conditions  mentioned  above,  but 
it  may  incidentally  be  mentioned  that  in  most  two-cycle 
engines  with  port  scavenging  in  which  the  ports  for  the 
scavenging  and  the  exhaust  are  of  the  same  width,  the  exhaust 
ports  have  a  length  of  some  22  to  30  per  cent,  of  the  total 
stroke  and  the  scavenging  ports  have  a  length  of  some  1 1 
to  15  per  cent.  They  may  each  exceed  this  figure  and  in 
larger  motors  may  become  as  much  as  35  per  cent,  for  the 
exhaust  port. 

As  regards  the  relative  length  of  the  main  and  auxiliary 
ports  where  there  are  auxiliary  ports  for  admission  of 
scavenging  air  after  the  exhaust  ports  have  closed,  in 
engines  of  moderate  size  up  to  200  or  300  B.H.P.  per  cylin- 
der, these  ma}^  be  made  approximately  equal,  but  in  very 
large  engines  it  will  be  found  desirable  to  have  the  main 
ports,  which  are  below,  comparatively  small,  whilst  the 
auxiliary  ports  are  very  much  larger.  The  ports  are  in 
any  case  made  to  slope  upwards  so  that  the  scavenging  air 
may  not  pass  directly  over  the  top  of  the  piston  to  the 
exhaust  ports. 

In  order  to  obtain  the  same  outputs  from  a  port  scaveng- 
ing engine  with  cylinders  of  the  same  dimensions  as  those  of 
a  valve  scavenging  motor,  it  is  essential  that  a  higher  mean 
effective  pressure  be  employed,  and  as  a  matter  of  fact, 
this  is  frequently  done  with  certain  motors  using  this 
principle.  For  instance  in  the  Sulzer  two-cycle  engine, 
both  of  the  marine  and  land  tj^e,  it  is  common  to  run 
the  engine  up  to  100  to  110  lb.  per  sq.  inch  as  a  mean 
effective  pressure  or  slightly  over,  and  the  indicator  cards 
given  in  Fig.  8  illustrate  this  fact.  In  this  case,  with 
a  four-cyhnder  engine,  the  mean  effective  pressures  taken 
from  the  various  cylinders  range  between  108  to  112  lb. 
per  sq.  inch,  the  mean  for  all  four  being  111  per  sq.  inch, 
giving  a  B.H.P.  power  of  795  B.H.P.  and  an  indicated  powder 
of  1,135,  or  an  efficiency  of  about  70  per  cent.,  which  is 
normal  for  a  two-stroke^motor. 


CHAPTER   IX 

THE  FUTURE  OF  THE  DIESEL  ENGINE 

The  possibilities  which  open  out  in  the  future  for  engines 
of  the  Diesel  or  similar  type,  are  so  wide  that  it  is  necessary 
to  restrain  a  natural  tendency  to  fall  into  immoderate 
language  when  touching  upon  this  point.  As  regards  the 
apphcations  of  the  engine  for  land  work,  but  little  is  left  to 
the  imagination,  so  thoroughly  has  it  taken  root  in  all  spheres 
of  engineering  industry.  Each  year  has  seen  engines  of 
larger  size  put  into  successful  operation,  and  at  the  time 
when  the  limit  seemed  to  have  been  approached  in  output 
for  the  four-cycle  engine,  the  development  of  the  two-cycle 
motor  reached  a  commercial  stage,  with  the  result  that  land 
engines  for  driving  dynamos  are  now  at  w^ork,  of  the  two- 
cycle  type,  in  powers  up  to  2,500  B.H.P.,  and  manufacturers 
are  prepared  to  take  orders  for  much  larger  outputs.  The 
future  then  of  the  Diesel  engine  of  the  stationary  type  for 
ordinary  work  is  no  longer  a  matter  of  speculation  and  can 
only  be  a  record  of  continued  progress  following  on  the 
success  already  attained. 

There  are  however  one  or  two  fields  in  which  the  Diesel 
engine  has  at  present  not  entered  to  any  large  extent,  and 
it  is  here  that  the  more  interesting  developments  may  be 
looked  for  in  the  course  of  the  next  few  years.  The  two  most 
important  of  these  have  reference  to  the  adoption  of  the 
Diesel  motor  for  locomotives,  and  for  motor  traction 
generally — motor  cars  and  buses,  and  tramcars. 

A  large  amount  of  work  has  already  been  put  on  the  ques- 
tion of  the  manufacture  of  a  locomotive  driven  by  Diesel 
engines  and  one  has,  in  fact,  actually  been  constructed  by 

336 


THE  FUTURE   OF  THE   DIESEL  ENGINE       ;}37 

Messrs.  Sulzer  Bros,  It  is  evident  that  the  saving  which 
could  be  effected,  were  all  the  practical  difficulties  overcome, 
would  be  enormous,  and  has  been  estimated  by  the  com- 
panies who  have  carefully  gone  into  the  matter  at  about 
75  per  cent,  of  the  present  fuel  running  costs. 

Though  it  is  too  wide  a  statement  to  say  that  a  direct 
driven  Diesel  locomotive  is  impracticable,  it  is  highly  probable 
that  before  such  a  stage  is  reached  on  a  commf^rcial  scale, 
another  means  will  first  be  adopted,  which  involves    less 
radical  difference  from  the  existing  methods  of  employment 
of  the  Diesel  engine.     At  the  present  time  it  is  hardly  unfair 
to  say  that  the  Diesel  motor  is  too  delicate  an  engine  to 
stand  the  great  strain  which  would  be  put  upon  it,  under 
working  conditions,  when  used  for  locomotive  driving,  and 
that  its  method  of  operation  should,  as  far  as  possible,  be 
the  same  as  with  ordinary  engines.     This,  apart  from  other 
considerations,  such  as  greater  starting  torque,  and  more  easy 
and  economical  variation  in  speed  of  running,  brings  us 
naturally  to  the  question  of  the  employment  of  electricity 
as  an  intermediary  between  the  engine  and  the  driving 
wheels  of  the  locomotive,  and  it  is  upon  these  lines  that  we 
may    expect    more    immediate    development.     With    this 
arrangement  a  non-reversible  Diesel  engine  may  be  coupled 
direct  to  a  dynamo,  delivering  its  power  to  motors  which 
drive  the  driving-wheels,  among  the  advantages  being  the 
employment  only  of  machinery  of  standard  type  (in  which 
a  very  large  amount  of  experience  has  been  gained),  great 
adhesion,   and   good   starting   torque.     Something   in   this 
direction  has  already  been  done  with  petrol  motors,  and 
petrol  electric  locomotives  are  now  comparatively  common 
on  the  Continent  for  use  on  branch  Hnes,  and  it  is  obvious 
that  if  there  is  an  economy  with  petrol  engines,  the  saving 
with  Diesel  engines  will  be  very  much  greater.     A  steam 
turbo-electric  locomotive  for  main  line  traffic  has  also  been 
constructed  in  this  country,  so  that  no  radically  new  depar- 
ture is  involved.     Up  to  the  present,  however,  direct  current 
dynamos  and  motors  have  been  employed,  which  is  not  by 
any  means  a  satisfactory  method,  and  it  is  probable  that  the 


THE   FUTURE   OF   THE   DIESEL  ENGINE        339 

Diesel  electric  locomotive,  of  which  much  may  be  expected 
in  the  future,  will  be  a  type  in  which  alternating  current 
dynamos  and  motors  will  be  employed,  working  on  one 
of  the  many  systems  which  have  been  proposed. 

The  problem  of  the  construction  of  a  Diesel-driven  loco- 
motive is  perhaps  of  greater  complexity  than  any  other  in 
connexion  with  this  motor,  and  certainly  the  difficulties 
encountered  are  far  in  excess  of  those  connected  with  the 
application  to  marine  work. 

Although  it  must  at  present  be  considered  only  in  an 
experimental  aspect,  a  large  locomotive  has  been  constructed 
by    Messrs.  .Sulzer    Bros.,  driven  by  a  Diesel  engme.     A 


Hd/ 


Fig.   171. — Diagram  illustrating  Arrangement  of  Sulzer  Diesel  Locomotive. 


four-cylinder  two-cycle  single-acting  motor  is  employed,  the 
arrangement  adopted  being  to  have  the  engine  with  cylinders 
coupled  in  pairs  at  an  angle  of  90°,  driving  on  to  an  inter- 
mediate crank  shaft  between  the  two  driving  shafts.  The 
cranks  are  at  180°,  and  it  is  stated  that  good  balancing  is 
obtained.  The  scavenge  pumps,  of  which  there  are  two,  are 
separate  from  the  engine  cyluiders  and  are  driven  by  levers 
from  the  connecting  rods  ;  they  are  placed  between  the  two 
pairs  of  cylinders,  being  vertical  and  arranged  longitudinally. 
In  order  to  provide  a  good  starting  torque  and  to  help  the 
engine  up  gradients,  an  auxiliary  air-compressor  is  provided, 
driven  by  a  vertical  two-cylinder  two-cycle  Diesel  engme,  the 
compressor  consisting  of  two  horizontal  cylinders.     When 


340  DIESEL  ENGINES  FOR  LAND  AND  MARINE  WORK 

greater  power  is  required  compressed  air  from  this  compressor 
and  more  fuel  are  supplied  to  the  working  cylinders,  with 
the  result  that  greater  power  is  obtained  for  a  short  time,  the 
auxiliary  plant  being  out  of  action  in  the  ordinary  way. 

A  very  large  reserve  of  compressed  air  is  carried,  many 
air-bottles  being  fitted  behind  the  engines,  whilst  there  is 
also  an  arrangement  for  cooling  and  circulating  water,  so 
that  the  consumption  of  water  is  infinitesimal  when  com- 
pared with  a  steam  locomotive.  The  power  developed  is 
about  1,200  B.H.P.,  and  the  entire  locomotive,  including 
fuel  and  water,  weighs  about  85  tons.  A  small  boiler  is 
provided  for  heating  the  train. 

It  cannot  be  long  also  before  very  serious  attention  will 
be  given  to  the  use  of  Diesel  engines  for  road  vehicles,  both 
motor  cars  and  buses  and  tramcars,  and  here  again,  at  any 
rate  in  the  first  instance,  it  is  probable  that  electricity  may 
bo  employed  in  the  same  wa3^  The  final  development, 
however,  is  difficult  to  forecast,  and  it  is  significant  to  note 
tliat  one  of  the  largest  firms  in  Germany  is  now  engaged  on 
the  perfection  of  a  small  Diesel  motor  suitable  for  direct 
driving  of  motor  vehicles. 

With  regard  to  the  aspect  of  the  marine  engine,  so  great 
are  the  possibilities  offered  that  it  is  easy  to  be  too  optimistic. 
There  does  not  seem  any  reason  to  suppose  that,  after  experi- 
ence has  been  gained,  there  should  be  any  doubt  as  to  the 
construction  of  engines  of  any  power  that  may  be  required 
for  the  largest  battleships  and  the  fastest  liners.  A  few 
years'  thorough  experience  is,  however,  necessary  before  such 
a  definite  revolution  can  be  effected,  but  as  so  much  time  and 
money  is  being  expended  in  the  matter,  and  as  moreover  the 
most  essential  difficulties  seem  to  have  been  overcome,  the 
ultimate  result  is  hardly  in  doubt.  When  it  is  remembered 
that  the  adoption  of  oil  engines  at  sea  on  a  large  scale  is 
probably  the  most  revolutionary  step  which  has  been  taken 
in  the  history  of  marine  engineering,  exceeding  in  its  impor- 
tance and  effect  the  introduction  of  the  steam  turbine,  it  will 
be  seen  that  a  too  rapid  culmination  is  not  to  be  reached, 
particularly  in  view  of  the  many  conflicting  interests  in- 


[To  face  page  340. 


THE  FUTURE   OF  THE   DIESEL   ENGINE       341 

volved.  Most  of  the  Admiralties  are  exercising  a  commend- 
able spirit  of  caution  and  endeavouring  to  carry  out  experi- 
ments on  a  large  scale,  the  effect  of  which  would  not  be 
disastrous  even  in  the  event  of  failure.  This  is  well  in- 
stanced in  the  case  of  the  British  Admiralty,  which  has 
designs  for  a  twin-screw  cruiser  with  a  Diesel  engine  (of 
6,000  H.P.)  on  one  shaft,  whilst  the  other  is  driven  by  a 
steam  set  in  the  usual  way.  In  the  case  of  another 
twin-screw  vessel  each  shaft  is  to  have  a  steam  turbine  and 
a  Diesel  engine,  with  a  clutch  between  so  that  the  engine 
drives  the  shaft  through  the  turbine,  which  is  only  in 
operation  at  high  speeds. 

Results  are  now  available,  after  nearl}^  three  years'  working 
of  a  10,000  ton  motor  ship,  the  Sehtndia,  in  which  the  power 
is  some  2,800  H.P.  These  indicate  conclusively  that  the 
economies  and  advantages  which  have  been  showTi  earlier 
in  this  volume  are  fully  confirmed.  The  consumption  of 
fuel  oil  for  all  purposes,  including  the  auxiliaries,  is,  on  an 
average  over  the  whole  period  of  working,  some  9^^  to  10  tons 
per  day,  as  against  40-45  tons  of  coal  which  Mould  be  re- 
quired for  a  similar  steamship.  The  cost  of  lubricating  oil 
is  not  appreciably  more  than  in  a  steamship,  and  the 
attendance  is  considerably  less.  During  the  first  eight 
months  it  was  in  commission  the  vessel  travelled  over 
40,000  miles,  and  the  engines  have  required  no  renewals 
or  repairs  of  importance,  other  than  the  replacement  of  the 
liner  in  one  cylinder,  which  cracked  owing  to  the  cooling 
water  passage  becoming  choked. 

The  largest  power  in  a  single  engine  yet  installed  in  a 
vessel  is  the  Reiherstieg  engine,  illustrated  earlier  in  this 
volume,  this  being  a  motor  of  about  2,000  B.H.P.  It  may 
be  said  at  once,  therefore, that,  as  regards  vessels  up  to  10,000 
tons  or  slightly  over,  the  employment  of  the  Diesel  engine  for 
propulsion  is  a  matter  of  accomplished  fact,  and  that 
success  has  been  achieved  in  every  direction.  Builders  of 
two-cycle  single-acting  engines  are  quite  prepared  to  con- 
struct motors  up  to  6,000  B.H.P. ,  and  those  of  four-cycle 
engines  up  to  2,000  B.H.P.,  so  that  no  difficulty  may  be 


342  DIESEL  ENGINES  FOR  LAND  AND  MARINE  WORK 

anticipated  for  vessels  up  to  18,000  B.H.P,  for  single-acting 
engines — a  figure  that  will  be  exceeded  in  a  year  or  two. 
Incidentally,  it  may  be  mentioned  that  two-cycle  Diesel 
engines  for  land  work  similar  to  the  marine  type  are  now 
on  order  for  4,000  B.H.P. 

The  possibilities  of  the  Diesel  motor  for  the  propulsion  of 
battleships  has,  perhaps  more  than  any  other  factor,  led  to 
great  attention  being  devoted  to  the  double-acting,  two- 
cycle  engine,  with  a  view  to  constructing  in  very  large 
powers,  Messrs.  Krupp  have  now  built  a  motor  of  this 
type  with  six  cylinders,  nominally  of  12,000  B.H.P.,  but 
probably  capable  of  developing  15,000  B.H.P.  The  motor 
battleship  thus  becomes  a  feasible  proposition  almost  at 
once,  since,  although  a  triple  screw  arrangement  giving 
45,000  H.P.  is  not  quite  sufficient  for  the  most  modern 
battle  cruisers,  it  is  not  likely  to  be  a  very  difficult  matter 
to  further  develop  the  engines  until  they  give  the 
necessary  power.  In  all  probability  motors  of  4,000  B.H.P. 
per  cylinder  will  be  built  shortly,  and  the  present  limit  may 
be  assumed  at  5,000  B.H.P.  per  cylinder. 

The  relatively  high  cost  of  Diesel  engines  compared  with 
steam  plant  has  been  urged  against  their  general  adoption, 
although  it  has  been  shown  in  Chapter  VI  how  quickly  this 
extra  capital  expenditure  is  cleared  off  in  a  very  short  time, 
owing  to  the  economies  effected.  Whilst  it  has  with  reason 
been  repeatedly  stated  earlier  in  this  book  that  Diesel 
engines  cannot  successfully  be  constructed  very  cheaply,  the 
cost  will  gradually  become  less,  and  will  not  greatly  exceed 
a  steam  installation  in  a  few  years.  At  the  present  time, 
it  must  be  remembered  that  most  large  motors  which  are 
constructed  are  built  to  special  designs,  since  improvements 
in  detail  are  continually  being  effected,  as  experience  is 
gained  at  sea.  The  result  is  that  no  general  standardization 
can  be  maintained,  even  by  a  particular  firm,  and  it  is  only 
by  standardization  that  material  cheapness  of  production 
can  be  attained.  This  state  of  affairs  must  continue  for  a 
year  or  two  longer,  but  at  the  present  time  the  cost  of  Diesel 
engines  of  the  two-cycle  single-acting  type  can  be  brought 


THE   FUTURE   OF  THE  DIESEL   ENGINE        343 

clown  to  £8  per  B.H.P.,  which  is  not  so  very  considerably  in 
excess  of  steam  plant. 

The  future  of  the  Diesel  engine,  both  for  land  and  marine 
work,  is,  to  a  very  large  extent,  bound  up  with  the  question 
of  the  oil  supply.  This  matter,  in  so  far  as  it  affects  Great 
Britain,  has  been  discussed  by  Dr.  Diesel  in  his  introduction, 
and  it  has  been  taken  up  by  the  British  Admiralty,  who 
appointed  a  Royal  Commission  to  investigate  it.  That  there 
is  sufficient  oil  for  all  requirements  for  some  time  to  come  is 
undoubted,  and  the  main  difficulties  to  be  encountered  are 
transport  and  storage.  So  far  as  merchant  vessels  are 
concerned,  this  is  not  generally  a  very  important  matter, 
since  their  trade  is  often  such  that  they  can  conveniently 
take  oil  on  board  at  ports  comparatively  near  the  oil-fields, 
where  the  cost  is  relatively  low.  For  naval  purposes, 
however,  and  those  vessels  which  find  it  necessary  to  take 
their  fuel  supply  either  in  Europe  or  some  distance  from  any 
oil  fields,  the  outlook  is  somewhat  difEerent.  If  the  cost  of 
transport  is  to  remain  such  as  will  cause  the  price  of  the  oil 
to  permit  of  little  or  no  economy  in  fuel  being  obtained,  as 
compared  with  the  use  of  coal  in  steamships,  this  might  to 
some  extent  retard  the  employment  of  Diesel  motors  in  such 
cases.  Even  then  it  would  not  be  a  serious  set-back,  as 
even  without  fuel  economy  the  other  advantages  of  the  oil 
engine  are  so  great  as  to  warrant  its  employment. 

It  is,  however,  to  be  anticipated  that  difficulties  regarding 
transport  or  storage  will  be  overcome  almost  immediately, 
as  the  shortage  of  oil- tank  ships  will  soon  be  at  an  end,  and 
storage  facilities  are  now  increasing.  The  question  of 
obtaining  fuel  oil  direct  from  coal,  as  outlined  by  Dr.  Diesel, 
has  not  yet  been  considered  on  a  large  scale  in  this  country  ; 
but  no  doubt  this  matter  will  receive  some  attention,  which 
it  undoubtedly  merits,  in  the  near  future 


APPENDIX 

LLOYD'S  RULES  FOR  INTERNAL  COMBUSTION 
MARINE  ENGINES— DIESEL'S  ORIGINAL 
PATENT 

The  following  rules  have  been  formulated  by  Lloyd's  Registry 
of  British  and  Foreign  Shipping  to  govern  the  application  of 
internal  combustion  engines  to  marine  propulsion.  The  rules 
however  are  not  in  all  cases  applicable  to  Diesel  engines  and  other 
similar  motors  working  with  high  initial  pressures,  and  for  such 
machines  special  regulations  will  shortly  be  issued. 

LLOYD'S   RULES   FOR   THE    SURVEY    OF    INTERNAL 
COMBUSTION  ENGINES  FOR  MARINE  PURPOSES 

General 

Section  1.  In  vessels  propelled  by  internal  combustion  engines, 
the  rules  as  regards  Machinery  will  be  the  same  as  those  relating 
to  steam  engines  so  far  as  regards  the  testing  of  material  used 
in  their  construction  and  the  fitting  of  sea  connexions,  discharge 
pipes,  shafting,  stern  tubes  and  propellers. 

Construction 

Section  2.  (I)  The  following  points  should  be  observed  in 
connexion  with  the  design  of  the  engines. 

(2)  The  shaft  bearings,  connecting  rod  brasses,  the  valve  gear, 
the  inlet  and  exhaust  valves  must  be  easily  accessible. 

(3)  The  reversing  gear  and  clutch  must  be  strongly  constructed 
and  easily  accessible  for  examination  and  adjustment. 

(4)  In  engines  of  above  60  B.H.P.  which  are  not  reversible 
and  which  are  manoeuvred  by  clutch,  a  governor  or  other  arrange- 
ment must  be  fitted  to  prevent  racing  of  the  engine  when  de- 
clutched. 

(5)  Efficient  positive  means  of  lubrication  (preferably  sight 
feed)  must  be  fitted  to  each  part  requiring  continuous  lubrication, 

(6)  If  the  engines  are  of  the  closed-in  type,  they  must  be  so 


346  APPENDIX 

fitted  that  the  contained  lubricating  oil  can  be  drained,  and  a 
metal  or  metal-lined  tray  must  be  fitted  to  prevent  leakage  of 
either  fuel  oil  or  of  lubricating  oil  from  saturating  the  wood  work, 

(7)  Carburettors,  where  petrol  is  used,  and  vaporizers,  where 
paraffin  is  used,  should  be  so  designed  that  when  the  engine  is 
stopjicd  the  fuel  sup])ly  is  automatically  shut  off.  If  an  over- 
flow is  provided  in  the  carburettor  or  vaporizer,  a  gauze-covered 
tray  with  means  of  draining  it  must  be  fitted  to  prevent  the  fuel 
from  flowing  into  the  bilges. 

Strong  metalUc  gauze  diaphragms  should  be  fitted  either  be- 
tween the  carburettor  (or  vaporizer)  and  cylinders  or  at  the 
air  inlets. 

(8)  If  the  ignition  is  electric,  either  by  magneto  or  by  coil  and 
accumulator,  all  electric  leads  must  be  well  insulated  and  suit- 
ably protected  from  mechanical  injury.  The  leads  should  be 
kept  remote  from  petrol  pipes,  and  should  not  be  placed  where 
they  may  be  brought  into  contact  with  oil. 

The  commutator  must  be  enclosed  ;  and  the  sparking  coils 
must  not  be  placed  where  they  can  be  exposed  to  explosive 
vapours. 

(9)  No  exposed  spark  gap  should  be  fitted. 

(10)  In  paraffin  and  heavy  oil  engines  where  lamps  are  used 
for  ignition  or  for  vaporizing,  these  lamps  should  be  fixed  by 
some  suitable  bracket,  and  the  flame  enclosed  when  in  use. 

(11)  The  circulating  pumps  sea  suction  is  to  have  a  cock  or 
valve  on  the  vessel's  skin  placed  on  the  turn  of  the  bilge  in  an 
easily  accessible  position,  and  the  circulating  pipe  is  to  be  pro- 
vided with  an  efficient  strainer  inside  the  vessel.  The  discharge 
overboard  is  to  be  fitted  with  a  cock  or  valve  on  the  vessel's 
skin  if  it  is  situated  under  or  near  the  load  line  of  the  vessel. 

(12)  A  bilge  pump  w^orked  by  engines  or  an  independent  power 
driven  bilge  pump  is  to  be  fitted,  to  draw  from  each  part  of  the 
vessel.  In  open  launches  this  bilge  pump  may  be  omitted 
provided  suitable  hand  pumps  are  fitted. 

(13)  The  cylinders  are  to  be  tested  by  hydraulic  pressure  to 
twice  the  working  pressure  to  which  they  will  be  subjected.  The 
water  jackets  of  the  cylinders  to  50  lb.  per  sq.  inch,  and  the 
exhaust  pipes  and  silencer  to  100  lb.  per  sq.  inch. 

(14)  The  exhaust  pipes  and  silencer  should  be  efficiently  water 
cooled  or  lagged  to  prevent  damage  by  heat,  and  if  the  exhaust 
is  led  overboard  near  the  water-line,  means  must  be  arranged 
to  prevent  water  being  syphoned  back  to  the  engine. 


APPENDIX 


347 


(15)  The  machinery  must  be  tried  under  full  nvorking  condi- 
tions, the  report  stating  the  approximate  speed  of  vessel,  the 
number  of  revolutions  of  the  engines  at  full  po\^  er,  both  ahead 
and  astern,  and  the  lowest  number  of  revolutions  of  the  engines 
which  can  be  maintained  for  manoeuvring  purposes. 

Rules  for  Determzning  Sizes  of  Shafts 

Section  3.  The  crank,  intermediate,  and  other  shafts  if  of 
ordinar}^  mild  steel  are  to  be  of  not  less  diameters  than  as  given 
in  the  following  table.  When  special  steel  is  used,  the  sizes  are  to 
be  submitted  for  consideration. 

(1)  For  petrol  or  paraffin  engines  for  smooth  water  services  : — 

3 

Diameter  of  crank  shaft  in  inches  =  0    ^  D  S 
where  D  =  diameter  of  cylinder  in  inches. 
S  =  stroke  of  piston  in  inches. 


Four  Stroke  Cjxle. 


For   1,  2,  3  or  4  Cyls. 

„       6  Cyls.        .      . 

»»       8     ,,  .       . 

12     „  .      . 


Two 
Stroke 
Cycle. 


Bearing 

between 

each  Crank. 


1  or  2  Cyls. 

3  ,, 

4  „ 
6     ., 


C  =  -34 
C  =  -36 
C  =  -38 
C  =  -44 


Two  Cranks 

between  the 

Bearings. 


C  =  -38 
C  =  -40 
C  =  -425 
C  =    49 


For  open  seas  service  add  -02  to  C. 

^1=  C    ^^  S   (71  3) 


Diameter  of    intermediate 
and  screw  shafts  in  inche 


where  D  =  diameter  of  cylinder  in  inches 
S  =  stroke  of  piston  in  inches. 
n  =  number  of  cylinders. 

For  smooth  water  services — 


C  =  '155  for  intermediate 
shafts. 

C  =  '170  for  screw  shafts 
fitted  with  continu- 
ous liners. 

C  =  "180  for  screw  shafts 
fitted  Avith  separate 
liners  or  with  no 
liners. 


For  open  seas  services— 
C  =  -165. 


C  =  -180. 


C  =  -190. 


348  APPENDIX 

In  engines  erf  two-stroke  cycle,  n  is  to  be  taken  as  twice  the 
number  of  cylinders. 

(2)  When  ordinary  deep  thrust  collars  are  used  the  diameter 
of  the  shaft  between  the  collars  is  to  be  at  least  fiths  of  that 
of  the  intermediate  shaft. 

(3)  In  the  cases  of  Diesel  and  other  Engines  in  which  very 
high  initial  pressures  are  employed,  particular^  should  be 
submitted  for  special  consideration. 

Fuel  Tanks  and  Connexions 

Section  4.  (1)  Separate  fuel  tanks  are  to  be  tested  with  all 
fittings  to  a  head  of  at  least  15  ft.  of  water.  If  pressure  feed  tanks 
are  employed,  they  are  to  be  tested  to  twice  the  working  pressure 
which  will  come  on  them  but  at  least  to  a  head  of  15  feet  of  water. 
If  the  tanks  are  made  of  iron  or  steel  they  should  be  galvanised. 

(2)  Strong  and  readily  removable  metallic  gauze  diaphragms 
should  be  fitted  at  all  openings  on  petrol  tanks. 

(3)  Paraffin  or  heavy  oil  tanks,  not  used  under  pressure,  are 
to  be  fitted  with  air  pipes  leading  above  deck.  Pressure-feed 
tanks  and  tanks  containing  petrol,  should  be  provided  with  escape 
valves  discharging  into  pipes  leading  to  the  atmosphere  above 
deck.  The  upper  ends  of  all  air  pipes  are  to  be  turned  down  and 
pipes  above  1  inch  diameter  are  to  be  provided  with  gauze 
diaphragms  at  the  end. 

(4)  No  glass  gauges  are  to  be  fitted  to  fuel  tanks  containing 
either  petrol,  paraffin  or  heavy  oil, 

(5)  Pilling  pipes  are  to  be  carried  through  the  deck  so  that 
the  gas  displaced  from  the  tanks  has  free  escape  to  the  atmo- 
sphere. 

(6)  Separate  fuel  tanks  should  be  provided  with  metal-lined 
trays  to  prevent  any  possible  leakage  from  them  floA\'ing  into 
the  bilges,  or  saturating  \^'ood\^ork.  Arrangements  are  to  be 
provided  for  emptying  the  tanks  and  draining  the  trays  beneath 
them.  For  petrol  tanks  the  trays  must  have  drains  leading 
overboard  where  possible  or  they  should  be  gauze-covered  trays 
with  means  for  draining  them. 

(7)  All  fuel  pipes  are  to  be  of  annealed  seamless  copper  with 
flexible  bends.  Their  joints  are  to  be  conical,  metal  to  metal. 
A  cock  or  valve  is  to  be  fitted  at  each  end  of  the  pipe  conveying 
the  fuel  from  the  tank  to  the  carburettor  or  vaporizer.  The 
fuel  pipes  should  be  led  in  positions  where  they  are  protected 


APPENDIX  349 

from  mechanical  injury  and  can  be  exposed  to  view  throughout 
their  whole  length. 

(8)  The  engine-room,  and  the  compartment  in  which  the  fuel 
tanks  are  situated,  are  to  be  efficiently  ventilated. 

(9)  An  approved  fire-extinguishing  apparatus  must  be 
supplied. 

Periodical  Surveys 

Section  5.  (1)  The  machinery  is  to  be  submitted  to  survey 
^.nnuall3^  At  these  surveys  the  cylinders,  pistons,  connecting 
rods,  crank  and  other  shafts,  inlet  and  exhaust  valves  and  gear, 
clutches,  reversing  gear,  propeller,  sea  connexions,  and  pumps 
are  to  be  examined.  The  electric  ignition  is  to  be  examined  and 
the  electric  leads  tested.  The  fuel  tanks  and  all  connexions  are 
to  be  examined,  and  if  deemed  necessary  by  the  Surveyor,  to  be 
tested  to  the  same  pressure  as  required  when  new.  If  prac- 
ticable, the  engines  should  be  tested  under  A\orking  conditions. 

(2)  The  screw  shaft  is  to  be  drawn  at  intervals  of  not  more 
than  two  years. 

THE  FOLLOWING  IS  A  COPY  OF  DR.  DIESEL'S 
ORIGINAL  SPECIFICATION,  DATED  AUGUST  27, 
18921 

COMPLETE  SPECIFICATION 

A  Process  for  Producing  Motive  Work  from  the  Combustion 

OF  Fuel 

The  working  process  of  the  hitherto  known  motor  engines 
using  the  combustion  heat  of  fuels  directly  in  the  cylinder  for 
performing  work  is  characterized  by  the  theoretical  indicator 
diagram  shown  in  Fig.  1  of  the  accompanying  drawing. 

On  the  curve  1 ,  2,  a  mixture  of  air  and  fuel  is  compressed,  at 
point  2  the  combustible  mixture  is  ignited  ;  by  the  now  following 
combustion  a  sudden  increase  of  pressure  from  2  to  3  is  produced 
which  is  accompanied  by  a  very  considerable  increase  of  tem- 
perature ;  the  explosion  like  combustion  is  such  a  quick  one,  that 
the  stroke  of  the  piston  during  the  combustion  is  nearly  zero. 
At  point  3  the  combustion  is  essentially  finished.    From  3  to  1 

'  Published  by  permission  of  the  Comptroller  of  the  Pfttopt  OfiBca. 


350  APPENDIX 

an  expansion  takes  place  in  performing  work,  whereby  pressure 
and  temperature  of  the  combustion  gases  decrease  again. 

In  all  hitherto  known  combustion  processes,  the  combustion 
process  is  left  to  itself  as  soon  as  the  ignition  takes  place,  the 
pressure  and  the  temperature  of  the  same  are  not  regulated  or 
controlled  during  the  proper  proceeding  of  combustion  in  pro- 
portion to  the  then  existing  volume  of  the  body  of  air. 

From  this  wrong  proportion  between  pressure,  temperature 
and  volume  result  in  all  these  processes  the  following  incon- 
veniences. 

(1)  The  temperature  produced  by  the  combustion  is  always  so 
high,  that  the  attainment  of  such  a  mean  temperature  of  the 
contents  of  the  cylinder  that  ^^■ill  render  possible  the  maintaining 
the  parts  tight,  the  lubrication  and  in  general  the  practical 
working  of  the  machine,  can  be  obtained  only  by  energetically 
coohng  the  cylinders  or  furnace-walls  respectively,  wherefrom 
\\ill  result  a  great  loss  of  heat. 

(2)  The  combustion  gases  are  insufificiently  cooled  by  the 
expansion  and  they  escape  while  still  in  a  very  hot  condition, 
which  constitutes  a  second  great  loss  of  heat. 

Also,  those  motor  engines  in  which  pm:e  air  is  compressed  from 
1  to  2  (see  Fig.  1 )  and  fuel  is  injected  suddenly  in  the  neighbour- 
hood of  point  2  while  igniting  the  same  simultaneously,  show  the 
increase  of  pressure  2,  3  combined  with  considerable  increase  of 
temperature. 

The  same  takes  place  in  motor  engines  which  drive  the  com- 
pression to  so  high  a  degree  that  the  mixture  is  ignited  spon- 
taneously by  the  temperature  produced  by  the  compression. 
The  igniting  points  of  the  most  part  of  fuels  are  very  low  (of 
petroleum  for  instance  at  from  70°  to  100°  C.)  ;  when  by  the  com- 
pression this  temperature  has  been  produced,  which  wiU  be  the 
case  already  at  low  pressures  (in  the  case  of  petroleum  at  a 
pressure  inferior  to  5  atmospheres,  in  the  case  of  gas  at  about 
15  atmospheres)  the  ignition  will  take  place  spontaneously.  The 
combustion  following  the  ignition  here  also  raises  the  tempera- 
ture very  considerably  and  produces  the  increase  of  pressure  2,  3 
(see  Fig.  1).  The  highest  tempera tm'e  or  combustion  temj^era- 
ture  occurring  during  the  combustion  is  entirely  independent  of 
the  burning  or  igniting  points,  which  depend  only  upon  the 
physical  properties  of  the  fuel. 

In  practice  the  explosion  or  combustion  process  requires 
a  material  time,  for  this  reason  the  line  2,  3  is  not  quite  vertical, 


APPENDIX 


L51 


but,  as  shown  in  dotted  lines,  somew  hat  mcluied  with  the  rounded 
transition  at  3. 

The  characteristic  feature  of  all  these  processes  remains, 
however  : — 

Increase  of  the  pressure  and  of  the  temperature  by  the  com- 
bustion and  during  the  latter,  and  the  subsequent  performance 


ZL2  APPENDIX 

of  work  by  erpansion.    The  process  of  combustion  after  ignition 
is  left  to  itself. 

The  new  process  hereinafter  described  differs  completely  from 
all  the  other  hitherto  kno\\n  processes.  It  is  represented  in  the 
theoretical  diagram  shown  in  Fig.  2.  In  this  process  pure  atmo- 
spheric air  is  compressed  in  a  cylinder  according  to  curve  1 ,  2  to 
such  a  degree,  that  by  this  compression  from  the  beginning 
before  any  combustion  takes  place,  the  highest  pressure  of  the 
diagram,  and  by  this  at  the  same  time,  the  highest  temperature 
is  produced,  that  is  to  say  the  temperature  at  which  the  subse- 
quent combustion  has  to  take  place,  namely  the  combustion 
temperature  (not  the  burning  or  igniting  point). 

If  it  be  desired,  for  instance,  that  the  later  combustion  shall 
take  place  at  a  temperature  of  700°  C,  the  pressure  will  be  of  64 
atmospheres  ;  for  800°  C.  the  pressure  will  be  of  90  atmospheres, 
and  so  on. 

Into  this  compressed  body  of  air  is  then  gradually  introduced 
from  outside  finely  divided  fuel,  which  ignites  as  the  air  mass  is 
heated  by  compression  far  above  the  temperature  necessary 
for  inflammation,  simultaneously  with  the  gradual  introduction 
of  fuel  an  expansion  of  the  body  of  air  takes  place,  which  is  regu- 
lated in  such  a  manner  that  the  cooling  caused  by  the  expansion 
destroys  at  each  moment  the  heat  produced  by  the  combustion 
of  the  several  introduced  particles  of  fuel.  Owing  to  this  the  com- 
bustion shows  its  effect  not  by  an  increase  of  temperature,  but 
solely  by  work  done  ;  and  also  not  by  an  increase  of  pressure,  as 
it  takes  place  in  consequence  of  the  simultaneous  expansion  at 
decreasing  pressure. 

The  combustion  takes  place  according  to  the  curve  2,  3  {Fig. 
2),  consequently  it  is  not  a  sudden  one,  but  it  takes  place  during 
an  exactly  prescribed  period  of  admission  of  fuel  during  the 
piston  stroke  w,  which  period  of  admission  is  regulated  and  deter- 
mined by  a  distributing  device,  and  which  has  for  its  result, 
that  the  combustion  proceeding  after  the  ignition  is  not  left  to 
itself,  but  is  regulated  during  its  whole  duration  in  such  a  manner 
that  pressure,  temperature  and  volume  are  in  a  prescribed  pro- 
portion. It  is  the  duration  of  this  admission  period  which  is 
fixed  by  the  distributing  device  ;  the  governor  also  influences  the 
duration  of  this  period,  which,  as  with  the  admission  period  of 
steam  engines,  may  be  of  10  per  cent,  and  more  of  the  piston's 
stroke,  but  under  certain  circumstances  may  be  reduced  to  a  less 
percentage  of  the  piston's  stroke. 


APPENDIX  3£3 

If  air  is  allowed  to  expand  without  any  supply  of  fuel,  the 
curve  2,  1  would  be  formed,  i.e.  the  expansion  would  do  no  work, 
but  give  back  simply  to  the  piston  the  previously  employed 
work  of  compression  ;  but  by  gradually  introducing  fuel  a  pres- 
sure difference  p  is  formed  at  any  place  between  the  curves  1 , 2  and 
2,  3,  in  consequence  whereof  the  expansion  work  becomes  greater 
than  the  compression  work,  and  a  useful  effect  is  performed. 

At  point  3  of  the  diagram  the  supply  of  fuel  ceases  and  the 
expansion  of  the  combustion  gases  goes  on  automatically  and 
performs  work  according  to  curve  3,  4.  As  the  pressure  at 
point  2  for  producing  the  highest  temperature  was  very  high  and 
is  still  very  high  at  point  3,  the  expansion  will  produce  from  3  to  4 
80  strong  a  cooling  of  the  gas  volume  that  in  leaving  the  engine  it 
will  carry  away  only  insignificant  quantities  of  heat. 

Here  also  the  comer  2  of  the  diagram  will  not  be  sharply  formed 
in  practice,  it  will  rather  assume  the  rounded  form  shown  in 
dotted  lines  ;  also  in  the  course  of  the  present  Specification 
terms  such  as  "  combustion  without  increase  of  temperature  " 
and  the  like  must  not  be  understood  in  the  exact  mathematical 
sense,  as  regard  is  to  be  paid  to  practice.  I  wish  only  to  have  it 
understood  that  in  the  new  process  the  highest  pressure  and  the 
highest  temperature  are  produced  essentially  not  by  combustion 
but  by  mechanical  compression,  and  that  by  the  combustion 
and  during  the  same  an  increase  of  temperature  does  not 
take  place  at  all  or  only  to  an  insignificant  degree,  at  all  events 
insignificant  if  compared  to  the  heating  by  compression. 

The  characteristic  feature  of  the  process  remains  always  as 
follows  : 

Increase  of  pressure  and  temperatiu-e  up  to  about  its  maximum 
not  by  combustion,  but  prior  to  the  combustion  by  mechanical 
compression  of  pure  air  and  hereupon  subsequent  performance 
of  work  by  gradual  combustion  during  an  exactly  prescribed  part 
of  the  expansion,  characterized  by  the  period  of  admission  of  fuel 
exactly  determined  by  the  distributing  device. 

According  to  what  has  been  said  above,  the  combustion  itself, 
in  opposition  to  all  the  hitherto  known  processes  of  combustion, 
does  not  produce  any  increase  of  temjDerature,  or  at  least  only 
an  unessential  one  ;  the  highest  temperature  is  produced  by  the 
compression  of  air  ;  it  is  therefore  under  control  and  will  be  kept 
correspondingly  in  moderate  hmits  ;  as  moreover  the  subsequent 
expansion  cools  the  body  of  gas  in  a  very  high  degree,  it  is  obvious 
that  no  artificial  cooling  of  the  cylinder  walls  is  necessary  ;   that 

A  A 


354  APPENDIX 

rather  the  mean  temperature  of  the  cylinder  contents  necessary 
for  keeping  the  parts  tight  and  lubricated,  and  in  general  for  the 
practical  working  of  the  engine,  is  obtained  solely  by  the  process 
itself,  whereby  also  it  differs  from  all  the  known  processes. 

Fig.  3  shows  a  further  modification  of  the  process  con- 
sisting in  that  the  first  period  of  the  air-compression  takes  place 
under  injection  of  water,  whereby  first  the  flatter  curve  1,  2  is 
formed,  and  that  then  only  the  second  part  of  the  compression 
without  water-injection  takes  place  according  to  the  steeper 
curve  2,  3  whereupon  the  combustion  and  expansion  is  conducted 
exactly  in  the  same  manner  as  m  Fig.  2.  By  this  means  I  attain 
considerably  higher  compression-pressures  than  in  Fig.  2  with- 
out reaching  too  high  temperatures  which  would  require  a  cooling 
of  the  cylinder. 

In  consequence  of  the  greater  fall  of  pressure  the  subsequent 
expansion  from  3  to  4  cools  the  body  of  the  gas  to  a  greater 
extent ;  the  exhaust  gases  escape  therefore  in  a  colder  condition 
than  in  Fig.  2  and  carry  awaj^  still  less  heat ;  this  modification 
of  the  process  gives  therefore  higher  useful  effects. 

The  exhaust  gases  may  in  this  case  be  cooled  even  below  the 
atmospheric  temperature  and  be  then  led  away  to  be  utiUzed 
for  refrigerating  purposes.  The  result  of  the  new  process  com- 
pared with  aU  the  other  hitherto  known  processes  is  a  considerable 
saving  on  fuel,  the  work  done  remaining  the  same. 

Any  kind  of  fuel  in  any  state  of  aggregation  is  suitable  for 
carrying  out  the  process. 

In  the  case  of  liquids  or  gases  or  vapours  respectively,  a  jet 
of  gas  or  liquid  is  dispersed  under  pressure  in  as  divided  a  state  as 
possible  into  the  body  of  compressed  air  during  the  period  of 
admission,  and  as  long  as  the  latter  lasts.  Solid  fuels  may  be 
introduced  in  a  pulverulent  or  dust-like  condition,  such  solid 
fuels  which  in  heating  agglomerate,  or  are  unsuitable  for  any 
other  reasons  for  being  used,  are  previously  gasified.  Liquid 
fuels  may  be  converted  previously  into  vapour  and  then  intro- 
duced in  this  form.  Matters  inflammable  with  diificulty  such  as 
anthracite  and  the  like,  may  be  mixed  with  readily  inflammable 
substances  such  as  petroleum  and  the  like. 

The  process  may  be  carried  out  in  a  single  or  double  acting 
vertical  or  horizontal  cylinder  witli  one  or  more  pistons  working 
on  the  same  flywheel  shaft  and  with  one  or  more  stages  of  com- 
pression and  expansion.  Figs.  4  ami  5  sliow  a  motor  engine  witli 
single  acting  cylinder  C  with  plunger  piston  P,  the  details  of 


APPENDIX  355 

which  are  constructed  for  high  pressures.  Piston  P  is  connected 
by  the  guide  a,  connecting  rod  h  and  crank  c  with  the  fly^vheel 
shaft  d  in  the  usual  manner. 

The  flywheel  shaft  drives  at  /  by  means  of  hyperbolic  toothed 
wheels  the  vertically  upward  extending  shaft  g  carrying  the 
governor  and  driving  the  horizontal  distributing  shaft  h. 

To  the  latter  are  secured  cams  i  which  at  the  right  moment 
open  the  air-valve  A  [Fig.  5)  and  the  fuel  valve  k.  The  gear  for 
the  latter  is  clearly  shown  in  Fig.  4  ;  for  the  valve  ^  it  is  of  similar 
construction.  As  soon  as  the  cams  i  are  out  of  action,  the  two 
valves  are  pressed  dowTi  against  their  seats  by  the  springs  I. 

The  process  which  according  to  this  invention  takes  place 
in  the  cj'linder  G  is  as  follows  : — 

(1)  DoAvnward  stroke  of  piston  P  produced  by  accumulated 
vis  viva  in  the  fly%vheel  from  the  preceding  working  strokes. 
Atmospheric  air  is  sucked  in  through  the  open  valve  A  into  the 
cylinder  C,  the  lowest  position  of  the  piston  is  showTi  in  dotted 
lines  in  Fig.  4  and  marked  with  1. 

(2)  Upward  stroke  of  the  piston  P  produced  also  by  the  accu- 
mulated vis  viva  of  the  flywheel,  the  valve  A  being  now  closed. 
The  air  previously  sucked  in  is  compressed  to  such  high  pressures, 
that  the  temperature  at  which  later  the  combustion  has  to  take 
place,  namely,  nearly  the  highest  temperature  of  the  process,  is 
produced  by  this  compression  alone. 

This  compression  pressure  is  determined  by  the  prescribed 
combustion  temperature  and  it  is  produced  by  the  piston  P, 
which,  in  its  dotted  end  position  2  {Fig.  4)  will  have  compressed 
the  quantity  of  air  dra^A'n  in  to  the  volume  corresponding  to  the 
prescribed  pressure. 

Such  pressures  cannot  be  obtained  if  from  the  beginning  fuel 
is  admixed,  to  the  air  such  as  for  instance  in  gas  and  petroleum 
motors,  as  in  this  case  already  at  low  pressures  at  intermediate 
points  of  the  stroke  namely  as  soon  as  the  igniting  point  of  the 
fuel  has  been  obtamed  (this  temperature  being  in  general  very 
low)  ignition  would  take  place,  and  in  consequence  thereof  inter- 
ruption of  the  prescribed  compression  by  combustion  would 
ensue  so  that  in  such  cases  it  would  be  impossible  to  carry  out 
the  prescribed  process. 

(3)  Second  downward  stroke  of  the  piston  P  or  true  working 
stroke. 

The  hopper  B  contams  pulverised  coal  introduced  through  the 
lateral  opening  n  shown  in  Fig.  5.     Tliis  hopper  is  shut  off  from 


356  APPENDIX 

the  cylinder  C  by  means  of  a  cock  D  rotated  by  the  distributing 
shaft  by  means  of  the  hyperboHcal  wheels  shown.  The  cock  is 
shown  to  a  larger  scale  in  four  positions  at  Fig.  6  ;  it  is  provided 
with  a  lateral  groove  r  which,  when  in  its  upper  position  a  is 
charged  with  coal  dust  arriving  from  the  hopper  B  ;  when  the 
cock  revolves,  the  groove  turns  towards  the  inside  of  the  cylinder 
(see  h)  ;  in  this  position  the  pressure  between  the  interior  of  the 
cylinder  and  the  groove  is  first  equalized,  as  the  loose  powder 
does  not  offer  any  obstacle  thereto  in  the  other  positions,  one 
of  which  is  shown  at  c ;  the  cock  allows  the  coal  dust  to  fall  into 
the  compressed  air  ;  owing  to  the  high  temperature  of  this  air 
the  coal  takes  fire  and  produces  heat,  which  immediately  in 
the  moment  of  its  production  is  converted  into  work  by  a  corre- 
sponding forward  movement  of  the  piston. 

The  introduction  of  the  powder  takes  place  gradually  in  a 
prescribed  space  of  time  in  a  manner  similar  to  the  sand  in  an 
hour  glass,  the  size  of  the  inlet  slit  determines  the  duration  of 
the  introduction  during  the  prescribed  period  of  admission  of 
the  fuel.  The  quantity  of  coal  is  determined  by  the  size  of  the 
groove  of  the  cock.  These  inner  organs  in  combination  with  the 
outer  distributing  device  insure  that  the  prescribed  duration 
of  admission  is  complied  with  and  that  the  last  coal  particles 
only  pass  in  when  the  piston  has  arrived  at  the  end  of  the  period 
of  admission. 

The  gradual  combustion  thus  described  consequently  con- 
tinues until  the  piston  has  arrived  in  its  position  3  (dotted  line  in 
Fig.  4).  At  this  moment  the  groove  of  the  cock  is  emptied  and 
passes  in  front  of  the  inlet  slit,  the  admission  of  fuel  is  therefore 
stopped.  The  air  mixed  with  the  combustion  gases  continues 
to  expand  automatically,  in  performing  work,  while  the  whole 
gas  body,  owhig  to  the  great  fall  of  pressure,  is  cooled  very 
considerably,  and  this  solely  by  doing  work  and  without  cooling 
the  cylinder  walls,  the  latter  being  suitably  insulated  by  a  jacket 
s  {Fig.  4). 

(4)  Second  upward  stroke  of  the  piston  P  produced  by  the 
vis  viva  of  the  flywheel. 

The  gas  body  is  driven  out  as  by  a  blowpipe,  through  the 
valve  A  (or  through  a  separate  blow-off  valve)  into  a  pipe  p 
{Fig.  5)  leading  it  away  ;  as  the  said  body  has  been  cooled  already 
previously  nearly  entirely  by  expansion,  it  carries  away,  as  a 
loss,  only  insignificant  quantities  of  heat.  The  residues  of  the 
combustion  are  contained  m  very  srnall  quantity  in  the  form  of  a 


APPENDIX  357 

fine  dust  suspended  in  tlie  rapidly  moving  and  Avliirling  gases 
of  combustion  and  are  consequently  also  simply  blown  out. 

After  this  second  upward  stroke  the  above  described  cycle  of 
operations  is  repeated. 

Tlie  motor  is  started  by  inti  educing  through  the  opening  r 
(Fig.  4)  compressed  air  from  a  store-vessel  by  means  of  a  pipe 
connected  therewith  at  g.  Tlie  store-vessel  is  kept  filled  Avith 
compressed  air  by  the  motor  during  the  working.  At  g^  a  special 
device  may  be  arranged  by  means  of  which  the  motor  may  be 
started  by  igniting  a  small  quantity  of  explosive  matter. 

The  regulating  of  the  machine  is  effected  by  means  of  the 
governor  E  of  any  known  construction,  which,  when  the  engine 
runs  too  fast,  prevents  the  fuel  from  falling  from  the  hopper 
into  the  groove.  The  small  coal  valve  k  is  opened  at  each  second 
revolution  by  means  of  the  cam  i  and  the  rod  m,  and  allows  a 
certain  quantity  of  coal  to  fall  into  the  groove. 

When  the  machine  works  too  fast  the  rod  n  connected  to  the 
governor  sleeve  moves  the  rod  m  so  as  to  bring  the  roller  attached 
to  the  lower  end  thereof  out  of  the  scope  of  the  cam  i  ;  the  valve 
k  therefore  remains  closed  and  no  coal  falls  into  the  cock,  and  in 
consequence  also  not  into  the  cylinder,  until  the  normal  speed 
has  been  re-established. 

The  above  described  motor  may  also  be  arranged  as  a  hoiizontal 
engine  ;  in  this  case  the  construction  of  the  parts  is  not  altered 
but  only  their  position.  In  lieu  of  a  plunger  piston  a  disc  piston 
may  be  employed,  so  that  the  cylinder  becomes  a  double  acting 
one. 

In  the  described  construction  the  engine  has,  as  in  most  of  the 
gas  motors,  only  a  working  stroke  at  every  second  revolut'on 
of  the  engine  shaft.  But  two  or  more  such  single-acting  cylin- 
ders may  be  coupled  to  the  same  flywheel  shaft,  whereby  the 
working  of  the  motor  becomes  more  uniform.  The  compression 
of  the  air  as  well  as  the  expansion  of  the  combustion  gases  may 
take  place  by  stages,  as  is  shown  by  way  of  example  in  Fig.  7. 

In  this  Fig.  7  the  valves  are  mdicated  only  diagrammatically, 
the  frame,  the  connecting  rod,  the  flywheel,  etc.,  are  omitted  ; 
all  these  parts  are  exactl3^  the  same  as  shown  in  Figs.  4  ami  5. 
There  are  in  Fig.  7  two  cylinders  G  with  plungers  P,  that  is  to 
say,  two  combustion  C3^1inders,  the  construction,  distributing 
devices,  etc.,  of  which  are  identical  to  those  of  the  cylinder 
represented  in  the  Figs.  4  a7ul  5.  These  two  cylinders  C  are 
connected  by  means  of  the  controlled  valves  b  to  the  two  sides  of 


358 


APPENDIX 


a  larger  central  cylinder  B  ;  by  the  two  valves  a  which  are  also 
controlled,  the  two  combustion  cylinders  are  in  communication 
with  the  air  vessel  L. 

The  cranks  of  the  two  cylinders  C  are  arranged  in  the  same 


Fig.  7 


position,  and  they  form  witli  the  crank  of  the  central  cylinder 
B  an  angle  of  180°. 

Tlie  working  of  this  construction  is  as  follows  :  The  piston  Q 
draws  in  air  by  its  upstroke  through  valve  d,  compresses  the 
latter  by  its  down  stroke  to  a  certain  pressure  and  then  forces 
the  air  through  valve  g  to  the  air  vessel  L. 

The  lower  part  of  the  central  cylinder  therefore  only  serves 
as  an  air  pump  and  effects  the  preparatory  compression  of  the 
combustion  air. 

This  preparatory  compression  should  go  only  to  such  an  extent 
that  the  heatmg  of  the  air  produced  by  this  compression  remains 
between  moderate  limits. 

Water  nozzles  are  arranged  still  at  gg  through  wliich  during 
the  preparatory  compression,  water  may  be  injected  at  a  low 
degree.  This  water  is  then  discharged  again  through  the  cock  h 
of  the  air  vessel. 

The  process  may  be  carried  out  either  with  or  without  injection 
of  water. 

The  action  in  the  cylinders  C  is  exactly  the  same  as  has  been 


APPENDIX  :^59 

described  with  reference  to  Figs.  4  ayid  5,  excepting  that  piston 
P  does  not  draw  in  the  air  from  the  atmosphere  during  its  down- 
stroke  but  from  vessel  L  in  which  the  air  is  aheady  under  pres- 
sure. At  its  upstroke  piston  P  therefore  effects  the  second  stage 
of  the  compression  up  to  the  prescribed  degree.  The  lower  and 
upper  end  positions  of  the  piston  are  shown  in  dotted  lines  and 
marked  with  1  and  2. 

Piston  P  now  moves  downward  again  to  position  3,  fuel  being 
during  this  time  gradually  introduced  and  the  combustion  con- 
trolled, as  above  described.  At  3  the  admission  of  fuel  ceases 
and  the  air  continues  to  expand  ;  when  the  piston  has  arrived 
in  its  lowest  position  1,  valve  b  opens,  piston  Q  is  at  this  moment 
just  in  its  upper  position  owing  to  the  arrangement  of  the  cranks  ; 
piston  P  then  moves  upward  and  piston  Q  do\Miward,  and  a 
further  expansion  of  the  combustion  gases  up  to  the  volume  of 
cylinder  B  takes  place  ;  hereupon  valve  b  closes  and  valve  / 
opens,  so  that  at  the  following  upward  stroke  of  piston  Q  the 
combustion  gases  are  expelled  through  valve  /  into  the  atmo- 
sphere, in  a  perfectly  cooled  condition,  as  their  entire  heat  will 
have  been  consumed  by  the  work  done  in  expanding. 

It  has  already  been  mentioned,  that  in  this  construction  the 
exhaust  gases  can  be  caused  to  escape  with  a  temperature  which 
is  below  that  of  the  atmosphere,  so  that  they  may  still  serve  for 
cooling  purposes. 

As  the  cylinders  C  have  a  combustion  period  only  at  each  second 
revolution  I  attain  by  arranging  two  such  cylinders  at  each 
revolution  a  combustion,  that  is  to  say  a  working  stroke  as  the 
combustion  is  made  to  take  place  alternately  on  the  right  and 
left  hand.  There  is  no  obstacle  to  using  only  one  combustion 
cylinder  in  place  of  two,  or,  on  the  other  hand,  more  than  two  in 
which  case  the  lower  part  of  the  cylinder  B  may  then  be  used 
as  an  expansion  cylinder ;  the  air  pump  for  the  preparatory 
compression  should  then  be  arranged  separatelj^  and  force  pre- 
viousl}^  compressed  air  into  the  reservoir  L. 

The  air  of  the  reservoir  L  serves  in  this  construction  directly 
for  starting  the  motor,  as  the  latter  may  be  fed  during  some 
revolutions  from  this  reservoir  with  full  pressure,  the  ignition 
only  taking  place  after  the  flpvheel  has  attained  the  necessary 
momentum. 

The  device  for  gradually  introducing  fuel  is  dependent  on  the 
peculiar  properties  of  the  material  employed. 

For  solid  pulverised  substances,  in  lieu  of  the  described  revolv- 


360  APPENDIX 

ing  cock,  a  powder  nozzle  or  a  small  pump  may  be  used  ;  for 
liquids  a  spray  nozzle  or  a  small  pump  is  employed,  for  gases 
also  a  small  pump  or  any  other  suitable  device  permitting  the 
gradual  introduction  of  the  fuel,  the  quantity  of  the  latter  being 
in  a  definite  proportion  to  the  piston's  stroke. 

Figs.  8  to  10  show  another  construction  of  a  motor  in  which 
liquid  fuel  is  employed  and  at  the  same  time  the  external  distri- 
buting device,  in  particular  the  device  for  gradually  introducing 
fuel,  is  of  a  quite  different  construction. 

This  machine  consists  of  two  entirely  identical  single  acting 
cylmders  provided  with  plunger  pistons,  the  cranks  of  which  are 
arranged  on  the  common  flywheel  shaft  in  the  same  position  ; 
the  frame,  fljrvvheel  and  distributing  device  are  nearly  exactly 
the  same  as  illustrated  in  Figs.  4:  and  5  and  therefore  not 
represented. 

The  combustion  in  the  cylinders  takes  place  alternately,  so 
that  at  each  revolution  a  working  stroke  is  effected. 

In  Fig.  8  one  of  the  cylinders  is  sho\A'n  m  vertical  section,  the 
other  in  front  view  with  its  insulating  casing. 

Fig.  9  is  a  front  view  of  the  cylinder  with  the  distributing 
device,  and  Fig.  10  a  plan  view  with  a  section  of  the  distributing 
devices. 

The  process  in  each  cylinder  is  the  same  as  described  with 
reference  to  Figs.  4  and  5,  viz.  : 

Drawing  in  of  air  through  valve  F,  then  compression  by  one 
stroke  up  to  the  end  position  2  of  the  piston  shown  in  dotted 
lines  ;  introduction  of  liquid  fuel  through  nozzle  D  and  combus- 
tion of  same  during  the  prescribed  period  of  admission  2,  3 
{Fig.  8),  finally  expansion  of  the  body  of  gas  and  escape  of  the 
same  through  valve  V  as  through  a  blowpipe  into  an  outward 
leading  pipe  R. 

As  the  drawing  in  follows  immediately  after  the  escape,  the 
valve  V  remains  open  during  a  whole  revolution,  and  then  closed 
during  a  whole  revolution.  This  simplest  possible  regulation 
is  effected  by  the  cam  S  {Figs.  9  and  10)  by  means  of  the  bent 
lever,  as  shown  in  the  drawing. 

The  cam  8  is  carried  by  the  distributing  shaft  W,  which  is 
driven  by  the  shaft  of  the  flywheel  in  a  similar  way  as  in  Figs. 
4  and  5.  The  nozzle  D  is  kept  closed  by  the  needle  n  and  serves 
for  gradually  admitting  the  fuel.  The  liquid  fuel  is  in  the  inner 
space  r  of  the  nozzle  D  and  is  maintained  there  by  means  of  a  feed 
pump  (not  shown)  provided  with  an  air  chamber  under  a  pressure 


362 


APPENDIX 


which  is  higher  than  the  highest  pressure  of  compression  of  the 
Air  in  the  cj-hnder. 

In  Fig.  10  is  shown  at  t  the  branch  pipe  for  the  Hquid  fuel 
coming  from  the  pump  and  leading  to  the  nozzle. 

At  the  moment  of  the  highest  compression,  i.e.  when  the  piston 
is  in  the  position  2,  the  needle  n  is  opened  by  the  distributing 

gear  and  allows  a 
sharp  thin  jet  of 
liquid  to  enter 
through  the  very 
small  opening  D,  as 
the  liquid  is  under 
a  pressure  superior 
to  the  cj^linder 
pres  sure.  This 
entrance  of  fuel 
continues  up  to 
position  3  of  the 
piston,  where  the 
distributing  device 
cuts  it  off  exactly, 
whereupon  the  com- 
bustion gases  con- 
tinue to  expand 
automatically. 

For  regulat  i  n  g 
the  jet  of  fuel  I 
have  provided  here 
exactly  the  same 
constru c t i o n  by 
which  in  Sulzer's 
valve  machines  the 
period  of  steam  ad- 
mission is  regu- 
lated. 
An  eccentric  E  moves  the  steel  side  piece  q  in  an  oviform  curve 
up  and  down  ;  the  steel  block  r  is  attached  to  the  rod  which 
actuates  needle  n  ;  as  soon  as  the  piece  q  moving  down\^ard 
strikes  against  the  piece  r  the  needle  is  opened  and  remains  open 
until  the  steel  piece  q  releases  the  piece  r.  As  the  piece  r  is  adjust- 
able from  the  governor  by  means  of  the  rod  St  (see  Fig.  9),  the 
governor  regulates  simultaneously  in  the  two  cylinders  the  dura- 


APPENDIX  303 

iiion  of  the  period  of  admission  of  fuel,  and  in  consequence  thereof 
the  speed  of  the  engine. 

In  Figs.  8  and  10  there  is  formed  round  the  nozzle  D  an  annular 
space  s  which  is  in  free  communication  with  the  interior  of  the 
cylinder. 

When  the  piston  moves  backward  under  decreasing  pressure 
the  air  flows  from  tliis  annular  space  back  into  the  cylinder  and 
serves  in  this  way  both  for  dividing  the  jet  of  fuel  and  for  pro- 
ducing turbulent  motion  for  distributing  the  combustion  heat 
over  the  whole  air  volume.  This  annular  space  s  is  only  of 
practical  importance  and  is  not  essential  for  the  process. 

There  is  moreover  in  Figs.  8  and  10  at  0  an  opening  for  intro- 
ducing compressed  air  or  gases  from  explosive  substances  serving 
to  start  the  motor.  When  in  Fig.  8  in  place  of  liquid,  gas  or 
vapour  is  compressed  in  the  inner  space  r  of  the  nozzle  D  the 
same  construction  may  be  employed.  It  is  therefore  not  neces- 
sary to  show  a  construction  of  engine  for  this  appUcation.  It  is 
especially  to  be  remarked  that  the  thermal  results  are  indepen- 
dent of  the  kind  of  gas  contained  in  the  cjlinder  ;  it  is  sufficient 
if  the  quantity  of  air  necessary  for  combustion  is  provided,  the 
other  considerable  quantit}^  of  gas,  which  acts  only  as  a  carrier 
of  heat,  may  consist  of  former  combustion  gases,  added  foreign 
gases  and  vapours  or  aqueous  vapour,  without  in  any  way  altering 
the  result.  It  follows  from  the  above  that  closed  engines  might 
be  arranged  so  as  to  take  up  at  each  stroke  only  a  small  quantity 
of  fresh  air  for  insuring  the  combustion,  but  \\  hicii  retain  essen- 
tially alwa3^s  the  same  body  of  gas,  a  small  exhaust  excepted. 
Having  now  particularly  described  and  ascertained  the  nature 
of  my  said  invention  and  in  what  manner  the  same  is  to  be  per- 
formed, I  declare  that  what  I  claim  is  : — 

(1)  The  method  of  working  combustion  motors  consisting  in 
comiDressing  in  a  cyhnder  by  a  working  piston,  pure  air,  or  other 
neutral  gas  or  vapour  together  with  pure  air,  to  such  an  extent, 
that  the  temperature  hereby  produced  is  far  higher  than  the 
burning  or  igniting  point  of  the  fuel  to  be  employed  (curve 
1-2  of  the  diagram  in  Fig.  2),  whereupon  fuel  is  supplied  at  the 
dead  centre  50  gradually,  that  on  account  of  the  outward  motion 
of  the  piston  and  the  consequent  expansion  of  the  compressed 
air  or  gas  the  combustion  takes  place  without  essential  increase 
of  temperature  and  pressure  (curve  2-3  of  the  diagram  in  Fig.  2) 
whereupon,  after  the  admission  of  fuel  has  been  cut  off,  the  fur- 
ther expansion  of  the  body  of  gas  contained  in  the  working 


S64  APPENDIX 

cylinder   takes   place   (curve   3-4   of   the   diagram   in  Fig.    2) 
substantially  as  described. 

(2)  The  mode  of  carrying  out  the  process  referred  to  in  the 
preceding  claim  with  multiple  compression  and  expansion  by 
providing  the  combustion  cylinder  on  one  hand  with  a  com- 
pressing pump  and  reservoir  and  on  the  other  hand  with  an  expan- 
sion cylinder,  or  by  coupling  several  combustion  cylinders  with 
each  other  or  with  the  said  compressing  pump  and  expansion 
oylinder,  substantially  as  described. 


INDEX 


A.B.  Diesels  INIotorer  engine,  74, 

191,  232 
Adiabatic  expansion,   10 
Adjustment  of  fuel  valve,  134 
Admiralty    specification    of    fuel 

oil,  54 
Advantages  of  various  engines, 

41 

—  - — •  two-cycle   engine,   44 

—  for  marine  work,   172 
Air  compressors,   115 

■ —  —  design  of,  321 
American  Diesel  engine,  300 
Analysis  of  fuel   oil,   53 
Asphalt  in  fuel   oil,   53 
Attendance  of  Diesel  engines,  131 
Augsbvirg  engine,  281 
Auxiliaries  for  motor  ships,  174, 
194,  200 

B 

Battleships,  Diesel  engines  for, 
203 

Bolinder  engine,  42 

British  Engine,  Boiler  &  Insur- 
ance Co.,   158 

Brons  engine,  42 

Burmeister  &  Wain  engine,  283 

C 
Cams,  65 

Capacity  of  air  compressors,  322 
Carels  engine,  78,   115,  223 
Cargo  capacity  of  motor  ships, 

176 
Clearance  space,  315 
Cockerill  engine,  229 
Combustion  in  Diesel  engine,  133 
Comj^arison  of  steam  and  Diesel 

engines,  142 


Comparison  of  steam  and  motor 

ships,  179 
Compressed    air    for    auxiliaries, 

198 
Constant  pressure  cycle,   14,   18 

—  temperature  cjcle,   14 
■ —  volume  cycle,   14,   16 
Consvmiption    of   fuel    in    Diesel 

engine,  25,  140,  151,  173, 

341 
Cooling  water  for  Diesel  engine, 

132 
Cost  of  Diesel  engines,  181 

oil,  50,   179 

operation,   138 

Crankshafts,  318 
Crosshead  engines,   186 
Cycle,  constant  pressiu-e,  14,  18 
— •  —  temperature,   14 

voluine,   14,   16 

• —  thermodynamic,   13 

—  working,   13 

—  Diesel,  21 

Cylinder     dimensions,      309 
Cylinders,  design  of,  303 

—  nvunber  of,   183 

D 

Daimler  engine,  296 

Design    of    Diesel    engines,    182, 

302 
Deutche-Amerikanische      Petro- 

leimi   Gesellschaft,   244 
Deutz  engine,  73,  86,   104 
Diameter  of  crankshafts,   318 
Dimensions  of  Diesel  engines,  357 
Double-acting  Diesel  engine,  39, 

45,  204 
Doxford  engine,  267 
Duplex  system  for  air  comj^res- 

sors,   199 


365 


366 


INDEX 


Diesel      engine,      A.B.      Diesels 
Motorer,  74,   191,  232 

attendance  of,  131 

Burmeister  &  Wain,   283 

—  —  Carels,  78,  115,  159,  217 
Cockerill,  229 

combustion  in,  35,   133 

consvunption  of,  25,   140, 

151,   173 

cooling  water,   132 

cost  of,   181 

—  • — •  cranlishafts,  318 
cycle,  21 

■ —  —  Daimler,  296 

—  —  design  of,   182,  302 

Deutz,  73,  86,  104 

■ —  ■ —  dimensions  of,  317 
Doxford,  267 

efficiency  of,  1,  24,  312 

for  batt'lesliips,  203 

for  submarines,  211 

fomidations  for,   126 

—  — ■  four  stroke  tyjie,  32,  58, 

63 
fuel  for,  3,  4,  5,  48 

—  —  futvire  of,  336 
governing,   77 

—  —  Gusto,  277 

—  —  high  speed,  40,  93 
•  horizontal,  100 

indicator    cards,    26,    29, 

34 
influence  of,  3 

—  —  Jimker's,  263,  300 

—  —  Kind,  300 

—  —  Kolomna,  291 

Krupp,  205,  244,  298 

■  limiting  power  of,  46 

locomotive,  337 

— •  —  management  of,   131 

M.A.N.,  65,  251,  281 

Mirrlees,  80,  85,  93 

Nederlandsche      Fabriek, 

87,  97,  267 

Nobel,  291 

oil  for,  3,  4,    5,  48 

Polar,  74,  191,  232 

port  scavenging,  191,  232 

reasons  for  high  efficiency, 

24 

—  —  reversing,   193 


Diesel  engine,  running,  61 

scavenging  in,   113,   187 

Sclineider-Carels,  226 

solid  injection,   122 

■  space  occupied,   126 

speed   of,    184,    252,    262, 

314 

starting  up,  35,  61,  131 

Sulzer,  99,  107,  206 

Tanner,  264 

—  - — ■  testing,   146 

•  two  cycle,  37,   107 

— -  —  double-acting,  39 

—  — •  valves  and  cams,  65 
■ — •  —  valves  of,  36,  65 

■ valve  setting  of,  27,  28 

weight   of,    48,    177,    202, 

251 

AVerkspoor,  87,  97,  267 

r  VVestgarth,  229 

—  —  Willans,  83 

E 

Eberle,  Chr.,   150 

Efficiency  of  Diesel  engine,  1, 
24,  312 

Electrically  driven  ships'  auxi- 
liaries, 200 

Emanuel  Nobel,  277 

Exhaust  ports,  dimensions  of,  334 

Expansion  of  gases,  9 

adiabatic,  10 

isothermal,  II 


Fomidations    for    Diesel    engine, 

126 
Four-stroke  cycle,  32,  58,   63 
France,  226 
Fuel  consmnption,  25,   140,   151 

^  of  niotor  ships,  201 

Fuel  for  Diesel  engines,  3,  4,  5, 

49 
Fviel  valve,  67 
■ — ■  - —  adjustment,   134 

for  tar  oil,  69 

Futiu'e  of  Diesel  engine,    337 

G 

Gases,  expansion  of,  9 
Germanischer  Llovd,  319 


INDEX 


307 


Governing  Diesel  engines,  77 
Gusto  engine,  277 

H 

Hamburg-South  American  Line, 

216 
High  speed  Diesel  engine,  40,  93 

Mirrlees,  93 

—  ^Verkspoor,  97 

Horizontal  engine,   100 
Horse-power   of  Diesel  engines, 

313 


Indicator  cards,  26,  29-31 
Injection  air,  quantity  of,  85 
Instriunents  for  testing,   147 
Isothermal  expansion,  11 


Junker's  engine,  263,  300 

K 

Kind  engine,  300 

Kolomna  engine,  291 

Krupp  engine,   205,  244,  298 


Lahmeyer,  159 

Leakage  past  piston,  136 

Lignite  oil,  3 

Limiting  power  of  Diesel  engines, 

46,   169 
Lloyd's,  319,  345 
Locomotive  with  Diesel  engine, 

337 
Longridge,  M.,   158 
Loss  of  comj^ression,   134 
Lvibrication,   137 
Lubricating  oil,   175 

INI 

M.A.N,   Diesel  engine,   65,   251, 

281 
Management    of    Diesel    engine, 

131 
JMauretania,   176 
Mean  effective  pressiu-e,  310 
Mechanical  efficiency,  312 
Mirrlees  engine,  80,  85,  93 


Motor  ships,  auxiliaries  for,  174, 
194 

cargo  capacity  of,    176 

comparison  with  steam- 
ships,  179 

Emanuel  Nobel,  277 

France,  226 

fuel     consimiption,     200, 

341 

machinery,  183 

power  to  drive,   175 

—  —  propeller  efficiency  of ,  177 
Rolandseck,  229 

Selandia,  283,  341 

Sembilan,  271 

staff  of,   181,  202 

Vulcanus,  267 

N 

Nederlandsche  Fabriek,   87,   97, 

267 
Nobel  engine,  291 
Nvmiber  of  cylinders,   183 

O 

Oil,  composition  and  analysis 
of,  53 

—  flash  point,  55 

—  lignite,  4 

—  Mexico,  52 

—  price  of,  50 

—  tar,  3,  51,  55 

—  Tarakan,  52 

—  Texas,  52 

—  Trinidad,  52 

—  vegetable  oil,  5 
Overload,   137 


Patent,  Diesel's  original,  349 
Piston  cooling,  273 

—  removal,   89 

—  sjaeed,  311 

—  volume  swept  tlirough,  315 
Pistons,  design  of,  306 
Polar  engine,  74,    191,  232 
Port  scavenging,   191,  331 
Power  of  various  engines,  43 

—  luniting,  46 

—  to  drive  motor  ships,  175 
Pressure  of  scavenging  air,    193 


368 


INDEX 


Price  of  oil,  51,  179 
Propeller     efficiency     of     motor 
ships,  177 

Q 

Quadruplex  compressor,   116 
Quantity  of  injection  air,   85 

R 

Reavell  compressor,   116 

Redwood,  B.,   160 

Reliability,   139,   171 

Reversing  Diesel  engines,  193, 
220,  233,  240,  246,  255, 
267,  275,  286,  294 

Rolandseck,  229 

Riuming  Diesel  engines,  61 

S 

Scavenge  pmnps,  217,  225,  232, 
253 

—  —  capacity  of,   187 

design  of,   189,  320 

Scavenging  air,  pressure  of,   193 

—  Diesel  engines,  113,  187,  219 
Schneider  engine,  226 
Seiliger,   167 

Selandia,  283,  341 

Sembilan,  271 

Solid  injection  engines,   122 

Sommer,  43 

Space  occupied  by  Diesel  engine, 

126 
Specification,  Admiralty,  54 

—  tar  oil,  55 

Speed  of  Diesel  engine,  184*  203, 

252,  262,  314 
Springs,   136 

Staff  of  motor  ships,  181,  202 
Starting  Diesel  engines,   35,   61, 

131 
Steam       engines,      comparative 

costs,   142 


Submarine  Diesel  engines,  211, 
282 

Sulzer  engine,  99,   107,  206 

indicator  cards,  30 

—  locomotive,  339 

Swan,  Htmter  &  Wigham  Rich- 
ardson, 236,  240 


Tanner  engine,  264 

Tar  oil  for  Diesel  engines,  3,  51, 

55 
Test  on  200  H.P.  engine,  150 
■ 300  H.P.  engine,   151 

—  —  500  H.P.  engine,   158 

high  sjDeed  engine,   167 

Testing  Diesel  engines,   146 
Thermodynamic  cycle,  13 
Trunk  piston,   186 
Two-cycle  Diesel  engine,  37,  106 

V 

Valves  of  Diesel  engine,  36 
Valve  setting,  27 
Van  de  Velde,   163 
Variation  of  speed,   185 
Vegetable  oil,  5 
Vickers  engine,   122 
Vulcanus,  267 

W 

Weight  of  Diesel  engines,  48,  177, 
202,  251 

—  - —  ships'  machinery,  177 
Werkspoor  engine,  87,  97,  267 
Westgarth  engine,  229 
Wilson,   163 

Willans  engine,  82 
Working  cycle,   13 


Zeitschrift  des    Vereins  deutscher 
Ingenieure,  167 


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SHORT=TITLE  CATALOG 

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Boulton,  S.  B.     Preservation  of  Timber.    (Science  Series  No.  82.) .  i6mo,  050 

Bourcart,  E.     Insecticides,  Fungicides  and  Weedkillers 8vo,  *4  50 

Bourgougnon,  A.    Physical  Problems.     (Science  Series  No.  ii3.).i6mo,  o  50 
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Bowie,  A.  J.,  Jr.     A  Practical  Treatise  on  Hydraulic  Mining 8vo,  5  00 

Bowles,  O.    Tables  of  Common  Rocks.     (Science  Series  No.  125.  i.i6mo,  050 

Bowser,  E.  A.     Elementary  Treatise  on  Analytic  Geometry              i2mo,  i  75 

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Brainard,  F.  R.     The  Sextant.     (Science  Series  No.  loi.) i6mo, 

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Brew,  W.     Three-Phase  Transmission 8vo,  *2  00 

Briggs,  R.,  and  Wolff,  A.  R.     Steam-Heating.     (Science  Series  No. 

67.) i6mo,  o  50 

Bright,  C.     The  Life  Story  of  Sir  Charles  Tilson  Bright Svo,  *4  50 

Brislee,  T.  J.     Introduction  to  the  Study  of  Fuel.     (Outlines  of  Indus- 
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Broadfoot,  S.  K.     Motors,  Secondary  Batteries.     (Installation  Manuals 

Series.) izmo,  *o  75 

Broughton,  H.  H.     Electric  Cranes  and  Hoists "9  00 

Brown,  G.     Healthy  Foundations.     (Science  Series  No.  80.) i6mo,  o  50 

Brown,  H.     Irrigation 8vo,  *5  00 

Brown,  Wm.  N.     The  Art  of  Enamelling  on   Metal i2mo,  ^i  00 


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Brown,    Wm.    N.      Dipping,    Burnishing,     Lacquering    and    Bronzing 

Brass  Ware i2mo,  *i  oo 

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■ History  of  Decorative  Art i2mo,  *i  25 

Workshop  Wrinkles 8vo,  *i  oi 

Browne,  C.  L.     Fitting  and  Erecting  of  Engines 8vo,  *i  50 

Browne,  R.  E.     Water  Meters.     (Science  Series  No.  81.) i6mo,  o  50 

Bruce,  E.  M.     Pure  Food  Tests i2mo,  *i  25 

Bruhns,  Dr.     New  Manual  of  Logarithms 8vo,  cloth,  2  co 

half  morocco,  2  50 
Brunner,  R.     Manufacture  of  Lubricants,  Shoe  Polishes  and  Leather 

Dressings.     Trans,  by  C.  Salter 8vo,  *3  00 

Buel,  R.  H.     Safety  Valves.     (Science  Series  No.  21.) i6mo,  o  50 

Burley,  G.  W.     Lathes,  Their  Construction  and  Operation lamo,  i  25 

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Buskett,    E.   W.     Fire    Assaying i2mo,  *i  25 

Butler,  H.  J.     Motor  Bodies  and  Chassis Svo,  *2  50 

Byers,  H.  G.,  and  Knight,  H.  G.     Notes  on  Qualitative  Analysis  ....  Svo,  *i  50 

Cain,  W.     Brief  Course  in  the  Calculus lamo,  *i  75 

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(Science  Series  No.  42.) i6mo,  o  50 

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■ Symbolic  Algebra.     (Science  Series  No.  73.) i6mo,  o  50 

Carpenter,  F.  D.    Geographical  Surveying.    (Science  Series  No.  37.).i6mo, 

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Carter,  E.  T.    Motive  Power  and  Gearing  for  Electrical  Machinery. Svo,  3  50 

Carter,  H.  A.     Ramie  (Rhea),  China  Grass i2mo,  *2  00 

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Gary,  E.  R.     Solution  of  Railroad  Problems  with  the  Slide  Rule.  .  i&mo,  *i  00 

Cathcart,  W.  L.     Machine  Design.     Part  I.  Fastenings Svo,  *3  00 

Cathcart,  W.  L.,  and  Chaffee,  J.  I.     Elements  of  Graphic  Statics  .  .    Svo,  *3  00 

■ Short  Course  in  Graphics i2mo,  i  50 

Caven,  R.  M.,  and  Lander,  G.  D.     Systematic  Inorganic  Chemistry. i2mo,  *2  00 

Chalkley,  A.  P.     Diesel  Engines Svo,  *3  00 

Chambers'  Mathematical  Tables Svo,  i  75 

Chambers,  G.  F.     Astronomy i6mo,  •  *i  50 

Charpentier,  P.     Timber Svo,  *6  00 

Chatley,  H.     Principles  and  Designs  of  Aeroplanes.     (Science   Series 

No.  126) i6mo,  o  50 

How  to  Use  Water  Power i2mo,  *i  00 

Gyrostatic  Balancing Svo,  *i  03 


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Child,  C.  D.     Electric  Arc 8vo, 

Child,  C.  T.     The  How  and  Why  of  Electricity i2mo, 

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Salter lamo, 

Christie,  W.  W.     Boiler-waters,  Scale,  Corrosion,  Foaming 8vo, 

Chimney  Design  and  Theory 8vo, 

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" Water:  Its  Purification  and  Use  in  the  Industries 8vo, 

Church's  Laboratory  Guide.     Rewritten  by  Edward  Kinch Svo, 

Clapperton,  G.     Practical  Papermaking Svo, 

Clark,  A.  G.     Motor  Car  Engineering. 

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Vol.  II.     Design {In  Press.) 

Clark,  C.  H.     Marine  Gas  Engines i2mo,     *i  50 

Clark,  J.  M.     New  System  of  Laying  Out  Railway  Turnouts i2mo,       i  00 

Clarke,  J.  W.,  and  Scott,  W.     Plumbing  Practice. 

Vol.      I.     Lead  Working  and   Plumbers'  Materials Svo,     *4  00 

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Fifth  Edition Svo,     *7  00 

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Clerk,  D.,  and  Idell,  F.  E.     Theory  of  the  Gas  Engine.     (Science  Series 

No.  62. ) i6mo,       o  50 

Clevenger,  S.  R.     Treatise  on  the  Method  of  Government  Surveying. 

i6mo,    morocco, 

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Cochran,  J.     Concrete  and  Reinforced  Concrete  Specifications Svo, 

Inspection  of  Concrete  Construction Svo, 

■ Treatise  on  Cement  Specifications Svo, 

Coffin,  J.  H.  C.     Navigation  and  Nautical  Astronomy i2mo, 

Colburn,  Z.,  and  Thurston,  R.  H.     Steam  Boiler  Explosions.     (Science 

Series  No.  2.) i6mo. 

Cole,  R.  S.     Treatise  on  Photographic  Optics i2mo, 

Coles-Finch,  W.     Water,  Its  Origin  and  Use Svo, 

Collins,  J.  E.     Useful  Alloys  and  Memoranda  for  Goldsmiths,  Jewelers. 

i6mo, 

Collis,  A.  G.     High  and  Low  Tension  Switc?i-Gear  Design Svo, 

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Comstock,  D.  F.,  and  Toland,  L.  T.    Modern  Theory  of  the  Constitution 

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Cooper,  W.  R.     Primary  Batteries Svo, 

Copperthwaite,  W.  C.     Tunnel  Shields 4to, 

Corey,  H.  T.     Water  Supply  Engineering Svo  {In  Press.) 

Corfield,  W.  H.     Dwelling  Houses.      Science  Series  No.  50.)  ....  i6mo, 

Water  and  Water-Supply.     (Science  Series  No.  17.) i6mo, 

Cornwall,  H.  B.     Manual  of  Blow-pipe  Analysis Svo, 


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8  D.  VAN  NOSTRAND  CO.'S  SHORT  TITLE  CATALOG 

Courtney,  C.  F.     Masonry  Dams 8vo,       3  50 

Cowell,  W.  B.     Pure  Air,  Ozone,  and  Water i2mo,     *2  00 

Craig,  J.  W.,  and  Woodward,  W.  P.     Questions  and  Answers  About 

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Craig,  T.     Motion  of  a  Solid  in  a  Fuel.     (Science  Series  No.  49. j   i6mo,       o  50 

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Cramp,  W.     Continuous  Current  Machine  Design 8vo,     *2  50 

Creedy,  F.     Single  Phase  Commutator  Motors 8vo,     *z  00 

Crocker,  F.  B.     Electric  Lighting.     Two  Volumes.     Svo. 

Vol.    I.     The  Generating  Plant 3  o') 

Vol.  IL     Distributing  Systems  and  Lamps 

Crocker,  F.  B.,  and  Arendt,  M.     Electric  Motors Svo,     *2  50 

Crocker,  F.  B.,  and  Wheeler,  S.  S.     The  Management  of  Electrical  Ma- 
chinery   1 2mo,     *i  00 

Cross,  C.  F.,  Bevan,  E.  J.,  and  Sindall,  R.  W.     Wood  Pulp  and  Its  Applica- 
tions.    (Westminster  Series.) Svo, 

Crosskey,  L.  R.     Elementary  Perspective Svo, 

Crosskey,  L.  R.,  and  Thaw,  J.     Advanced  Perspective Svo, 

CuUey,  J.  L.     Theory  of  Arches.     (Science  Series  No.  S7.) i6mo, 

Dadourian,  H.  M.     Analytical  Mechanics i2mo, 

Dana,  R.  T.    Handbook  of  Construction  plant i2mo,  leather, 

Danby,  A.     Natural  Rock  Asphalts  and  Bitumens Svo, 

Davenport,  C.     The  Book.      (Westminster   Series. ) Svo, 

Davey,  N.    The  Gas  Turbine Svo, 

Davies,  F.  H.     Electric  Power  and  Traction Svo, 

Foundations  and  Machinery  Fixing,     dnstallat'on  Manual  Series.) 

6mo, 

Dawson,  P.     Electric  Traction  on  Railways Svo, 

Deerr,  N.     Sugar  Cane Svo, 

Deite,  C.     Manual  of  Soapmaking.     Trans,  by  S.  T.  King 4to, 

DelaCoux,  H.    The  Industrial  Uses  of  Water.    Trans,  by  A.  Morris.  Svo, 

Del  Mar,  W.  A.     Electric  Power  Conductors Svo, 

Denny,  G.  A.     Deep-level  Mines  of  the  Rand 4to, 

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De  Roos,  J.  D.  C.     Linkages.     (Science  Series  No.  47.) i6mo, 

Derr,  W.  L.     Block  Signal  Operation Oblong  i2mo, 

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Desaint,  A.     Three  Hundred  Shades  and  How  to  Mix  Them Svo, 

De  Varona,  A.     Sewer  Gases.     (Science  Series  No.  55.) i6mo, 

Devey,  R.  G.     Mill  and  Factory  Wiring.     (Installation  Manuals  Series.) 

i2mo, 
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Dichmann,  Carl.     Basic  Open-Hearth  Steel  Process i2mo, 

Dieterich,  K.     Analysis  of  Resins,  Balsams,  and  Gum  Resins Svo, 

Dinger,  Lieut.  H.  C.     Care  and  Operation  of  Naval  Machinery       i2mo, 
Dixon,  D.  B.     Machinist's  and  Steam  Engineer's  Practical  Calculator. 

i6mo,  morocco,       i  25 
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D.  VAN  NOSTRAND  CO.'S  SHORT  TITLE  CATALOCi  9 

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folio,  *4  00 

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Down,  P.  B.     Handy  Copper  Wire  Table i6mo,  *i  00 

Draper,  C.  H.     Elementary  Text-book  of  Light,  Heat  and  Sound  .  .  i2mo,  i  00 

Heat  and   the   Principles   of   Thenno-dynamics izmo,  *2  00 

Dron,  R.  W.     Mining  Formulas i2mo,  i  00 

Dubbel,  H.     High  Power  Gas  Engines 8vo,  *5  00 

Duckwall,  E.  W.     Canning  and  Preserving  of  Food  Products 8vo,  *5  00 

Dumesny,  P.,  and  Noyer,  J.     Wood  Products,  Distillates,  and  Extracts. 

8vo,  *4  50 
Duncan,  W.  G.,  and  Penman,  D.     The  Electrical  Equipment  of  Collieries. 

8vo,  *4  00 
Dunstan,  A.  E.,  and  Thole,  F.  B.  T.     Textbook  of  Practical  C.iemistry. 

r2mo,  *i  40 

Duthie,  A.  L.     Decorative  Glass  Processes.     (Westminster  Series. ).  Svo,  *2  00 

Dwight,  H.  B.     Transmission  Line  Formulas Svo,  *2  00 

Dyson,  S.  S.     Practical  Testing  of  Raw  Materials Svo,  *5  00 

Dyson,  S.  S.,  and  Clarkson,  S.  S.     Chemical  Works Svo,  *7  50 

Eccles,  R.  G.,  and  Duckwall,  E.  W.     Food  Preservatives  .  .  .   Svo,  paper,       0  50 

Eccles,  W.  H.     Wireless  Telegraphy  and  Telephony ( /;/   Press.) 

Eck,  J.     Light,  Radiation  and  Illumination.     Trans,  by  Paul  Hogner, 

Svo, 

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Edelman,  P.  Inventions  and  Patents lamo.   (/;/  Press.) 

Edgcumbe,  K.     Industrial  Electrical  Measuring  Instruments Svo, 

Edler,  R.     Switches  and  Switchgear.     Trans,  by  Ph.   Laubach.  .  Svo, 

Eissler,  M.     The  Metallurgy  of  Gold Svo, 

The  Metallurgy  of  Silver Svo, 

— —  The  Metallurgy  of  Argentiferous  Lead Svo, 

A  Handbook  on  Modem  Explosives Svo, 

Ekin,  T.  C.     Water  Pipe  and  Sewage  Discharge  Diagrams folio. 

Electric  Light  Carbons,  Manufacture  of Svo, 

Eliot,  C.  W.,  and  Storer,  F.  H.     Compendious  Manual  of  Qualitative 

Chemical  Analysis i2mo, 

Ellis,  C.     Hydrogenation  of  Oils Svo, 

Ellis,  G.     Modem  Technical  Drawing Svo, 

Ennis,  Wm.  D.     Linseed  Oil  and  Other  Seed  Oils Svo, 

Applied  Thermodynamics Svo, 

Flying  Machines  To-day iimo, 

Vapors  for  Heat  Engines i2mo, 

Erfurt,  J.     Dyeing  of  Paper  Pulp.     Trans,  by  J.  Hubner 

Ermen,  W.  F.  A.     Materials  Used  in  Sizing Svo, 

Erwin,  M.     The  Universe  and   the  Atom (In   Press. ) 

Evans,  C.  A.     Macadamized  Roads (/«  Press.) 


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10        D.  VAN  NOSTRAND  CO.'S  SHORT  TITLE  CATALOG 

Ewing,  A.  J.     Magnetic  Induction  in  Iron 8vo,     *4  00 

Fairie,  J.     Notes  on  Lead  Ores i2mo, 

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Fairley,  W.,  and  Andre,  Geo.  J.     Ventilation  of  Coal  Mines.     ^  Science 

Series  No.  58.) i6mo, 

Fairweather,  W.  C.     Foreign  and  Colonial  Patent  Laws 8vo, 

Falk,  M.   S.     Cement  Mortars  and   Concretes 8vo, 

Fanning,  J.  T.     Hydraulic  and  Water-supply  Engineering 8vo, 

Fay,  I.  W.     The  Coal-tar  Colors. 8vo, 

Fernbach,  R.  L.     Glue  and  Gelatine 8vo, 

Chemical  Aspects  of  Silk  Manufacture i2mo, 

Fischer,  E.     The  Preparation  of  Organic  Compounds.     Trans,  by  R.  V. 

Stanford , i2mo, 

Fish,  J.  C.  L.     Lettering  of  Working  Drawings Oblong  8vo, 

• Mathematics  of  the  Paper  Location  of  a  Railroad,  .paper,   i2mo, 

Fisher,  H.  K.  C,  and  Darby,  W.  C.     Submarine  Cable  Testing  .  .  .  .8vo, 
Fleischmann,  W.     The  Book  of  the  Dairy.     Trans,  by  C.  M.  Aikman. 

8vo,       4  00 
Fleming,  J.  A.     The  Alternate-current  Transformer.     Two  Volumes.  8vo. 

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Vol.  n.     The  UtiUzation  of  Induced  Currents *5  00 

Fleming,  J.  A.     Propagation  of  Electric  Currents 8vo,     *3  00 

A  Handbook  for  the  Electrical  Laboratory  and  Testing  Room.     Two 

Volumes 8vo,  each,     *5  00 

Fleury,  P.     Preparation  and  Uses  of  White  Zinc  Paints 8vo,     *2  50 

Flynn,  P.  J.     Flow  of  Water.     (Science  Series  No.  84.) i2mo,       o  50 

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Forgie,  J.     Shield   Tunneling 8vo.    (In   Press.) 

Foster,  H.  A.     Electrical  Engineers'  Pocket-book.      uSerenth  Edition.) 

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Foster,  Gen.  J.  G.     Submarine  Blasting  in  Boston  1  Mass.;  Harbor    4to,       3  50 

Fowle,  F.  F.     Overhead  Transmission  Line  Crossings i2mo,     *i  50 

The  Solution  of  Alternating  Current  Problems 8vo  (In  Press.) 

Fox,  W.  G.     Transition  Curves.     (Science  Series  No.  no.) i6mo,       0  50 

Fox,  W.,  and  Thomas,  C.  W.     Practical  Course  in  Mechanical  Draw- 
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Foye,  J.  C.     Chemical  Problems.     (Science  Series  No.  69.) i6mo, 

Handbook  of  Mineralogy.     (Science  Series  No.  86.) i6mo, 

Francis,  J.  B.     Lowell  HydrauUc  Experiments 4^0, 

Franzen,  H.     Exercises  in  Gas  Analysis i2mo, 

French,  J.  W.     Machine  Tools,  2  vols 4*0, 

Freudemacher,   P.    W.     Electrical    Mining   Installations.     (Installation 

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Frith,  J.     Alternating  Current  Design 8vo, 

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^  "  8vo,     *4  00 


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Fuller,  G.  W.     Investigations  into  the  Fhirification  of  the  Ohio  River. 

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Gant,  L.  W.     Elements  of  Elsctric  Traction 8vo,     *2  50 

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Garforth,  W.  E.     Rules  for  Recovering  Coal  Mines  after  Explosions  and 

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Gaudard,  J.     Foundations.     (Science  Series  No.  34.' i6mo,       050 

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Geikie,  J.     Structural  and  Field  Geology Svo, 

Mountains.     Their   Growth,    Origin   and    Decay Svo, 

The  Antiquity  of  Man  in  Europe Svo, 

Georgi,   F.,   and   Schubert,   A.     Sheet   Metal   Working.     Trans,   by   C. 

Salter Svo, 

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Gas  Lighting      (Science  Series  No.  in.) i6mo, 

Household  Wastes.     (Science  Series  No.  97.) i6mo, 

House  Drainage.     (Science  Series  No.  63.) i6mo, 

Gerhard,  W.  P.     Sanitary  Drainage  of  Buildings.    (Science  Series  No.  93.) 

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Gerhardi,  C.  W.  H.     Electricity  Meters Svo, 

Geschwind,    L.     Manufacture    of   Alum   and    Sulphates.     Trans,    by    C. 

Salter Svo, 

Gibbs,  W.  E.     Lighting  by  Acetylene i2mo, 

Gibson,  A.  H.     Hydraulics  and  Its  Application Svo, 

Water  Hammer  in  Hydraulic  Pipe  Lines i2mo, 

Gibson,  A.  H.,  and  Ritchie,  E.  G.    Circular  Arc  Bow  Girder 4to, 

Gilbreth,  F.  B.     Motion  Study i2mo, 

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Primer  of  Scientific  Management i2mo, 

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Gillmore,  Gen.  Q.  A.     Limes,  Hydraulic  Cements  at  d  Mortars Svo, 

Roads,  Streets,  and  Pavements i2mo, 

Godfrey,  E.     Tables  for  Structural  Engineers i6mo,  leather, 

Golding,  H.  A.     The  Theta-Phi  Diagram i2mo, 

Goldschmidt,  R.     Alternating  Current  Commutator  Motor Svo, 

Goodchild,  W.     Precious  Stones.     (Westminster  Series.) Svo, 


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00 

2 

00 

*I 

25 

*2 

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50 

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*i 

25 

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00 

*2 

00 

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12        D.  VAN  NOSTRAND  CO.'S  SHORT  TITLE  CATALOG 

Gooieve,  T.  M.     Textbook  on  the  Steam-engine.  .    i2mo, 

Gor;,  G.     Ihctrolytic  Separation  of  Metals 8vo, 

Goali,  E.  S.     Arithmetic  of  the  Steam-engine i2mo, 

Calculus.      (Science  Series  No.  112.) i6mo, 

High  Masonry  Dams.     (Science  Series  No.  22.) i6mo, 

Practical  Hydrostatics  and  Hydrostatic  Formulas.     (Science  Series 

No.  117.) i6mo, 

Gratacap,  L.  P.     A  Popular  Guide  to  Minerals 8vo, 

Gray,  J.     Electrical  Influence  Machines i2mo, 

— • —  Marine  Boiler  Design i2mo, 

Greenhill,  G.     Dynamics  of  Mechanical  Flight 8vo, 

Greenwood,  E.     Classified  Guide  to  Technical  and  Commercial  Books.  Svo, 

Gregorius,  R.     Mineral  Waxes.     Trans,  by  C.  Salter i2mo, 

Griffiths,  A.  B.     A  Treatise  on  Manures i2mo, 

Dental  Metallurgy Svo, 

Gross,  E.     Hops Svo, 

Grossman,  J.     Ammonia  and  Its  Compounds i2mo, 

Groth,   L.  A.     Welding  and  Cutting   Metals   by   Gases   or  Electricity. 

(Westminster   Series) Svo, 

Grover,  F.     Modern  Gas  and  Oil  Engines Svo, 

Gruner,  A.     Power-loom  Weaving Svo, 

Giildner,  Hugo.     Internal  Combustion  Engines.     Trans,  by  H.  Diederichs. 

4to,  *io  00 

Gunther,  C.  0.     Integration 

Gurden,  R.  L.     Traverse  Tables folio,  half  morocco, 

Guy,  A.  E.     Experiments  on  the  Flexure  of  Beams Svo, 

Haenig,  A.     Emery  and  Emery  Industry Svo, 

Hainbach,  R.     Pottery  Decoration.     Trans,  by  C.  Salter i2mo. 

Hale,  W.  J.     Calculations  of  General  Chemistry i2mo, 

Hall,  C.  H.     Chemistry  of  Paints  and  Paint  Vehicles i2mo, 

Hall,  G.  L.    Elementary  Theory  of  Alternate  Current  Working.  ..  .8vo, 

Hall,  R.  H.     Governors  and  Governing  Mechanism i2mo. 

Hall,  W.  S.     Elements  of  the  Differential  and  Integral  Calculus Svo, 

Descriptive  Geometry Svo  volume  and  a  4to  atlas, 

Haller,  G.  F.,  and  Cunningham,  E,  T.     The  Tesla  Coil i2mo, 

Halsey,  F.  A.     Slide  Valve  Gears i2mo, 

■  The  Use  of  the  Slide  Rule.     (Science  Series  No.  114.) i6mo, 

Worm  and  Spiral  Gearing.     (Science  Series  No.  116.) i6mo, 

Hamilton,  W.  G.     Useful  Information  for  Railway  Men i6ino. 

Hammer,  W.  J.     Radium  and  Other  Radio-active  Substances Svo, 

Hancock,  H.     Textbook  of  Mechanics  and  Hydrostatics Svo, 

Hancock,  W.  C.   Refractory  Materials.  ( Metallurgy  Series. )    (/;;  Press.) 

Hardy,  E.     Elementary  Principles  of  Graphic  Statics 12  mo,     *i  50 

Haring,  H.     Engineering  Law. 

Vol.  I.     Law  of  Contract Svo,     *4  00 

Harris,  S.  M.     Practical  Topographical  Surveying {In  Press.) 

Harrison,  W.  B.     The  Mechanics'  Tool-book i2mo,       i  50 

Hart,  J.  W.     External  Plumbing  Work Svo,     *3  00 

Hints  to  Plumbers  on  Joint  Wiping Svo,     *3  00 


*7 

50 

*i 

23 

*2 

50 

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00 

*i 

00 

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00 

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50 

*2 

00 

*2 

23 

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50 

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25 

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50 

0 

50 

0 

50 

I 

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*I 

00 

I 

50 

D.  VAN  XOSTRAXD  CO.'S  SHORT  TITLE  CATALOG        13 

Principles  of  Hot  Water  Supply 8vo,     *3  00 

Sanitary  Plumbing  and  Drainage 8vo,     *3  00 

Haskins,  C.  H.     The  Galvanometer  and  Its  Uses i6mo,       i  50 

Hatt,  J.  A.  H.     The  Colorist square  i2mo,     "^  i  50 

Hausbrand,  E.     Drying  by  Means  of  Air  and  Steam.     Trans,  by   A.  C. 

Wright i2mo,     *2  00 

Evaporating,  Condensing  and  Cooling  Apparatus.     Trans,  by  A.  C. 

Wright 8vo,     *5  00 

Hausmann,   E.     Telegraph   Engineering 8vo,     *3  00 

Hausner,  A.     Manufacture  of  Preserved  Foods  and  Sweetmeats.     Trans. 

by  A.  Morris  and  H.  Robson Svo,     *3  00 

Hawkesworth,  J.     Graphical  Handbook  for  Reinforced  Concrete  Design. 

4to, 

Hay,  A.     Alternating  Currents Svo, 

Electrical  Distributing  Networks  and  Distributing  Lines Svo, 

Continuous  Current  Engineering Svo, 

Hayes,  H.  V.    Public  Utilities,  Their  Cost  New  and  Depreciation. .  .8vo, 

Public  Utilities,  Their  Fair  Present  Value  and  Return Svo, 

Heather,  H.  J.  S.     Electrical  Engineering Svo, 

Heaviside,  O.     Electromagnetic  Theory.      Vols.  I  and  n.  .  .  .Svo,  each. 

Vol.  Ill Svo, 

Heck,  R.  C.  H.     The  Steam  Engine  and  Turbine Svo, 

Steam-Engine  and  Other  Steam  Motors,     Two  Volumes. 

Vol.    I.     Thermodynamics  and  the  Mechanics Svo, 

Vol.  II.     Form,  Construction,  and  Working Svo, 

Notes  on  Elementary  Kinematics Svo,  boards, 

Graphics  of  Machine  Forces Svo,  boards, 

Heermann,  P.     Dyers'  Materials.     Trans,  by  A.  C.  Wright i2mo, 

Heidenreich,    E.    L.      Engineers'    Pocketbook    of    Reinforced    Concrete, 

i6mo,  leather, 
Hellot,  Macquer  and  D'Apligny.   Art  of  Dyeing  Wool,  Silk  and  Cotton.  Svo, 

Henrici,  0.     Skeleton  Structures Svo, 

Bering,  D.  W.     Essentials  of  Physics  for  College  Students Svo, 

Hering-Shaw,  A.     Domestic  Sanitation  and  Plumbing.     Two  Vols..    Svo, 

Hering-Shaw,  A.     Elementary  Science Svo, 

Herrmann,  G.     The  Graphical  Statics  of  Mechanism.     Trans,  by  A.  P. 

Smith i2mo, 

Herzfeld,  J.     Testing  of  Yarns  and  Textile  Fabrics Svo, 

Hildebrandt,  A.     Airships,  Past  and  Present Svo, 

Hildenbrand,  B.  W.    Cable-Making.     (Science  Series  No.  32.).  ..  .i6mo, 

Hilditch,  T.  P.     A  Concise  History  of   Chemistry lamo,     *i  25 

Ilill,   C.   S.     Concrete   Inspection i6mo,     *i  00 

Hill,  J.  W.    The  Purification  of  Public  Water  Supplies.     New  Edition. 

(Ill    Press.) 

Interpretation   of   Water   Analysis (In   Press.) 

Hill,  M.  J.  M.     The  Theory  of  Proportion Svo,     *2  50 

Hiroi,  I.    Plate  Girder  Construction.     (Science  Series  No.  95.)...i6mo,      o  50 

Statically-Indeterminate   Stresses lamo,     ^2  00 

Hirshfeld,  C.  F.    Engineering  Thermodynamics.  (Science  Series  No.  45.) 

i6mo,      o  50 


^2 

50 

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50 

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50 

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50 

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00 

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00 

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50 

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00 

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50 

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50 

*3 

50 

*5 

DO 

*i 

00 

*i 

00 

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50 

''3 

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*2 

00 

I 

50 

*I 

7.S 

*5 

00 

*2 

00 

2 

00 

*3 

50 

'3 

50 

0 

50 

14       D.  VAN  NOSTRAND  CO.'S  SHORT  TITLE  CATALOG 

Hobart,  H.  M.     Heavy  Electrical  Engineering 8vo,     *4  50 

Design  of  Static  Transformers i2mo,     *2  00 

Electricity 8vo,     *2  oo 

Electric  Trains 8vo,     *2  50 

Hobarl,  H.  M.     Electric  Propulsion  of  Ships 8vo,     *2  00 

Hobart,  J.  F.    Hard  Soldering,  Soft  Soldering  and  Brazing i2mo,     'i  00 

Hobbs,  W.  R.  P.    The  Arithmetic  of  Electrical  Measurements.  ..  .i2mo,      o  50 

Koff,  J.  N.     Paint  and  Varnish  Facts  and  Formulas izmo,     *i  50 

Hole,  W.     The  Distribution  of  Gas 8vo,     *7  50 

Holley,  A.  L.     Railway  Practice folio,      6  00 

Holmes,  A.  B.    The  Electric  Light  Popularly  Explained.  ..lamo,  paper,       o  50 

Hopkins,  N.  M.     Experimental  Electrochemistry 8vo, 

Model    Engines    and    Small    Boats i2mo,       i  25 

Hopkinson,  J.,  Shoolbred,  J.  N.,  and  Day,  R.  E.     Dynamic  £le:tricity. 

( Science  Series  No.  71. ) i6mo, 

Horner,  J.     Practical  Ironfounding 8vo, 

— —  Gear  Cutting,  in  Theory  and  Practice 8vo, 

Houghton,  C.  E.    The  Elements  of  Mechanics  of  Materials i2mo, 

Houllevigue,  L.     The  Evolution  of  the  Sciences 8vo, 

Houstoun,  R.  A.    Studies  in  Light  Production i2mo, 

Hovenden,  F.     Practical  Mathematics  for  Young  Engineers i2mo, 

Hov.-e,  G.     Mathem.atics  for  the  Practical  Man i2mo, 

Hov/orth,  J.     Repairing  and  Riveting  Glass,  China  and  Earthenware. 

8vo,  paper, 

Hubbard,  E.     The  Utilization  of  Wood-waste 8vo, 

Hubner,  J.    Bleaching  and  Dyeing  of  Vegetable  and  Fibrous  Materials. 

i  Outlines  of  Industrial  Chemistry.) 8vo, 

Hudson,  0.  F.    Iron  and  Steel.  .(Outlines  of  Industrial  Chemistry. ) .8vo, 
Humphrey,  J.  C.  W.     Metallography  of  Strain.     (Metallurgy  Series.) 

(/;;  Press.) 
Humphreys,  A.  C.     The  Business  Features  of  Engineering  Practice.. 8vo, 

Hunter,  A.    Bridge  Work 8vo.   (/;;  Press.) 

Hurst,  G.  H.     Handbook  of  the  Theory  of  Color 8vo, 

Dictionary  of  Chemicals  and  Raw  Products 8vo, 

Lubricating  Oils,  Fats  and  Greases 8vo, 

Soaps 8vo, 

Hurst,  G.  H.,  and  Simmons,  W.  H.    Textile  Soaps  and  Oils 8vo, 

Hvrsl,  H.  E.,  and  Lattey,  R.  T.     Text-book  of  Physics 8vo, 

■ Also   published   in  three  parts. 

Part      I.    Dynamics  and  Heat 

Part    II.     Sound  and  Light 

Part  III.     Magnetism  and  Electricity 

Hutchinson,  R.  V/.,  Jr.     Long  Distance  Electric  Power  Transmission. 

123^.0,     *3  00 
Hutchinson,  R.  W.,  Jr.,  and  Thomas,  W.  A.    Electricity  in  Mining.  i2mo, 

(Ln  Press.) 
Hutchinson,  W.  B.     Patents  and  How  to  Make  Money  Out  of  Them. 

i2mo,       1  25 

Hutton,  W.  S.     Steam-boiler  Con-.truction 8vo,       6  co 

The  Works'  Manager's  Handbook 8vo,       6  00 


0 

50 

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00 

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00 

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00 

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25 

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50 

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2 

50 

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00 

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00 

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50 

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00 

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25 

*I 

25 

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50 

0 

53 

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50 

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00 

*2 

00 

*2 

00 

*2 

03 

*2 

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2 

50 

*2 

50 

D    \AN  NOSTRAXD  CO.'S  SHORT  TITLE  CATALOG        15 

Hyde,  E.  W.     Skew  Arches.     (Science  Series  No.  15.) i6mo,       0  50 

Hyde,  F.  S.     Solvents,  Oils,  Gums,  Waxes 8vo,     '2  00 

Induction  Coils.     fScience  Series  No.  53.) i6mo, 

Ingham,  A.  E.    Gearing.    A  practical  treatise 8vo, 

Ingle,  H.     Manual  of  Agricultural  Chemistry 8vo, 

Inness,  C.  H.     Problems  in  Machine  Design i2mo, 

Air  Compressors  and  Blowing  Engines i2mo, 

Centrifugal  Pumps i2mo, 

The  Fan i2mo, 

Isherwood,  B.  F.     Engineering  Precedents  for  Steam  Machinery    .   8vo, 
Ivatts,  E.  B.     Railway  Management  at  Stations 8vo, 

Jacob,  A.,  and  Gould,  E.  S.     On  the  Designing  and  Construction  of 

Storage  Reservoirs.     'Science  Series  No.  6 i6mo,       o  50 

Jannettaz,  E.     Guide  to  the  Determination  of  Rocks.     Trans,  by  G.  W. 

Plympton i2mo,       i  50 

Jehl,  F.     Manufacture  of  Carbons 8vo,     *4  00 

Jennings,  A.  S.     Commercial  Paints  and  Painting.    (Westminster  Series. ) 

8vo,     ~2  00 

Jennison,  F.  H.     The  Manufacture  of  Lake  Pigments 8vo,     *3  00 

Jepson,  G.     Cams  and  the  Principles  of  their  Construction 8vo,     *i  50 

— —  Mechanical  Drawing 8vo  'In  Pre  para!  ion.) 

Jervis-Smith,   F.   J.     Dynamometers 8vo,     *3  50 

Jockin,  W.     Arithmetic  of  the  Gold  and  Silversmith i2mo,     *i  00 

Johnson,  J.   H.     Arc  Lamps  and  Accessory  Apparatus.     (Installation 

Manuals  Series.) i2mo,     *o  75 

Johnson,  T.  M.     Ship  Wiring  and  Fitting.     (Installation  Manuals  Series.) 

i2mo,     *o  75 

Johnson,  W.  McA.     The  Metallurgy  of  Nickel tin  Preparation.) 

Johnston,  J.  F.  W.,  and  Cameron,  C.     Elements  of  Agricultural  Chem-istry 

and  Geology i2mo, 

Joly,  J.     Radioactivity  and  Geology. i2mo, 

Jones,  H.  C.     Electrical  Nature  of  Matter  and  Radioactivity i2mo, 

Evolution  of  Solutions {In  Press. ) 

New  Era  in  Chemistry i2mo, 

Jones,  J.  H.     Tinplate  Industry Svo, 

Jones,  M.  W.     Testing  Raw  Materials  Used  in  Paint i2mo, 

Jordan,  L.  C.     Practical  Railway  Spiral i2mo,  leather, 

Joynson,  F.  H.     Designing  and  Construction  of  Machine  Gearing  .  .  8vo, 
Jiiptner,  H.  F.  V.     Siderology :  The  Science  of  Iron Svo, 

Kansas  City  Bridge 4to, 

Kapp,  G.     Alternate  Current  Machinery.      Science  Series  No.  96.). i6mo, 

Keim,  A.  W.     Prevention  of  Dampness  in  Buildings 8vo,     *2  00 

Keller,  S.  S.     Mathematics  for  Engineering  Students.     i2mo,  half  leather. 

Algebra  and  Trigonometry,  with  a  Chapter  on  Vectors *i  75 

Plane  and  Solid  Geometry *i  25 

and  Knox,  W.  E.     Analytical  Geometry  and  Calculus *2  00 

Kelsey,  W.  R.     Continuous-current  Dynamos  and  Motors 8vo,     *2  50 


2 

60 

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00 

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00 

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6 

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0 

50 

l6        D.  VAN  NOSTRAND  CO.'S  SHORT  TITLE  CATALOG 

Kemble,  W.  T.,  and  Underbill,  C.  R.     The  Periodic  Law  and  the  Hydrogen 

Spectrum 8vo,  paper,  *o  50 

Kemp,  J.  F.     Handbook  of  Rocks 8vo,  *i  50 

KendiU,  E.     Twelve  Figure  Cipher  Code 4to,  *i2  50 

Kennedy,  A.  B.  W.,  and  Thurston,  R.  H.     Kinematics  of  Machinery. 

(Science  Series  No.  54.) i6mo,  o  50 

Kennedy,    A.  B.  W.,  Unwin,  W.  C,  and  Idell,  F.  E.     Compressed   Air. 

(Science  Series  No.  106.) i6mo,  o  50 

Kennedy,  R.     Modern  Engines  and  Power  Generators.  Six  Volumes.  4to,  15  00 

Single  Volumes each,  3  00 

Electrical  Installations.     Five  Volumes 4to,  15  00 

Single  Volumes each,  3  50 

Flying  Machines;  Practice  and  Design i2mo,  *2  00 

Principles  of  Aeroplane  Construction 8vo,  *i  50 

Kennelly,  A.  E.     Electro-dynamic  Machinery 8vo,  i  50 

Kent,  W.     Strength  of  Materials.     (Science  Series  No.  41.) i6mo,  o  50 

Kershaw,  J.  B.  C.     Fuel,  Water  and  Gas  Analysis 8vo,  *2  50 

Electrometallurgy.     (Westminster  Series.) 8vo,  *2  00 

The  Electric  Furnace  in  Iron  and  Steel  Production i2mo,  *i  50 

Electro-Thermal    Methods    of   Iron   and    Steel    Production.  ..  .8vo,  *3  00 

Klndelan,  J.     Trackman's  Helper i2mo,  *i  50 

Kinzbrunner,  C.     Alternate  Current  Windings 8vo,  *i  50 

Continuous  Current  Armatures , 870,  *i  50 

Testing  of  Alternating  Current  Machines 8vo,  *2  00 

Kirkaldy,  W.  G.    David  Kirkaldy's  System  of  Mechanical  Testing.  .4to,  10  00 

Kirkbride,  J.     Engraving  for  Illustration 8vo,  *i  50 

Kirkham,  J.  E.     Structural  Engineering 8vo,  '''s  00 

Kirk  wood,  J.  P.     Filtration  of  River  Waters 4to,  7  5t> 

Kirschke,  A.     Gas  and  Oil  Engines i2mo,  *i  25 

Klein,  J.  F.     Design  of  a  High-speed  Steam-engine 8vo,  *5  00 

— —  Physical  Significance  of  Entropy 8vo,  *i  50 

Kleinhans,  F.  B.     Boiler  Construction 8vo,  3  00 

Knight,  R.-Adm.  A.  M.     Modern  Seamanship 8vo,  *7  50 

Half  morocco *9  00 

Knott,  C.  G.,  and  Mackay,  J.  S.     Practical  Mathematics 8vo,  2  oo 

Knox,  J.     Physico-Chemical  Calculations i2mo,  *i  00 

Fixation  of  Atmospheric  Nitrogen.      ( Chemical  Monographs. )  .  i2mo,  *o  75 

Koester,  F.     Steam-Electric  Power  Plants 4to,  *5  00 

Hydroelectric  Developments  and  Engineering 4to,  ^^5  00 

Koller,  T.     The  Utilization  of  V/aste  Products 8vo,  *3  00 

Cosmetics 8vo,  *2  50 

Kremann,  R.     Application  of  the   Physico-Chemical  Theory   to   Tech- 
nical  Processes    and   Manufacturing   Methods.     Trans,    by   H. 

E.  Potts 8vo,  '2  50 

Kretchmar,  K.     Yarn  and  Warp  Sizing 8vo,  *4  00 

Lallier,  E.  V.     Elementary  Manual  of  the  Steam  Engine i2mo,  *2  00 

Lambert,  T.     Lead  and  Its  Compounds 8vo,  *3  50 

Bone  Products  and  Manures 8vo,  *3  r  0 


D.  VAX  NOSTRAND  CO.'S  SHORT  TITLE  CATALOG 


17 


Lamborn,  L.  L.     Cottonseed  Products 8vo,     *3  00 

Modern  Soaps,  Candles,  and  Glycerin 8vo,     *7  50 

Lamprecht,  R.     Recovery  Work  After  Pit  Fires.    Trans,  by  C.  Salter  8vo,     *4  00 

Lancaster,  M.     Electric  Cooking,  Heating  and  Cleaning 8vo,     *i  50 

Lanchester,  F.  W.     Aerial  Flight.     Two  Volumes.     Svo. 

Vol.  I.     Aerodynamics *6  00 

Aerial  Flight.     Vol.  IL     Aerodonetics *6.oo 

Lange,  K.  R.     By-Products  of  Coal-Gas  Manufacture i2mo,      2  00 

Larner,  E.  T.     Principles  of  Alternating  Currents i2mo.     *i  25 

La  Rue,  B.  F.     Swing  Bridges.     (Science  Series  No.  107.) i6mo,       o  50 

Lassar-Cohn.   Dr.     Modern   Scientific   Chemistry.     Trans,   by   M.    M. 

Pattison  Muir i2mo,     *2  00 

Latimer,  L.  H.,  Field,  C.  J.,  and  Howell,  J.  W.     Incandescent  Electric 

Lighting.     (Science  Series  No.  57.)     i6mo,       0  50 

Latta,  M.  N.     Handbook  of  American  Gas-Engineering  Practice  .  .   Svo,     *4  50 

—  — •  American  Producer  Gas  Practice 4to,     *6  00 

Laws,  B.  C.     Stability  and  Equilibrium  of  Floating  Bodies Svo,     *3  50 

Lawson,    W.    R.      British    Railways.      A    Financial    and    Commercial 

Survey Svo,       2  00 

Leask,  A.  R.     Breakdowns  at  Sea i2mo,       2  00 

— —  Refrigerating  Machinery i2mo,       2  00 

Lecky,  S.  T.  S.     "  Wrinkles  "  in  Practical  Navigation Svo,     *8  00 

Le  Doux,  M.     Ice-Making  Machines.     (Science  Series  No.  46.)     i6mo,      0  50 
Leeds,   C.    C.     Mechanical    Drawing    for   Trade    Schools.      ( Machinery 

Trades  Edition.)    oblong    4to     *2  00 

Mechanical  Drawing  for  High  and  Vocational  Schools 4to,     *i  50 

Lefevre,  L.     Architectural  Pottery.     Trans,  by  H.  K.  Bird  and  W.  M. 

Biims 4to,     *7  50 

Lehner,  S.     Ink  Manufacture.     Trans,  by  A.  Morris  and  H.  Robson  Svo,     *2  50 

Lemstrom,  S.     Electricity  in  Agriculture  and  Horticulture Svo,     '^i  50 

Letts,  E.  A.     Fundamental   Problems   in  Chemistry Svo,     '2  00 

Le  Van,  W.  B.    Steam-Engine  Indicator.    (Science  Series  No.  78.)i6mo,       o  50 
Lewes,  V.  B.     Liquid  and  Gaseous  Fuels.     (Westminster  Series.) .   Svo,     *2  00 

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Lewis,  L.  P.     Railway  Signal  Engineering Svo,     *3  50 

Lieber,  B.  F.     Lieber's  Standard  Telegraphic  Code Svo,   *io  00 

Code.     German  Edition Svo,   *io  00 

Spanish  Edition Svo,   *io  00 

French  Edition Svo,   *io  00 

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Bankers  and  Stockbrokers'  Code  and  Merchants  and  Shippers' 

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100,000,000  Combination  Code Svo,  *io  00 

Engineering  Code Svo,  *i2  50 

Livermore,  V.  P.,  and  Williams,  J.     How  to  Become  a  Competent  Motor- 
man  i2mo,     *i  00 

Livingstone,  R.     Design  and  Construction  of  Commutators Svo,     *2  25 

Mechanical  Design  and  Construction  of  Generators Svo,     *3  50 

Lobben,  P.     Machinists'  and  Draftsmen's  Handbook Svo,       2  50 


l8        D.  VAN  NOSTRAND  CO.'S  SHORT  TITLE  CATALOG 

Lockwood,  T.  D.  Electricity,  Magnetism,  and  Electro-telegraph ....  8vo,  2  50 
Lockwood,  T.  D.     Electrical  Measurement  and  the  Galvanometer. 

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Lodge,  O.  J.  Elementary  Mechanics i2mo,  i  50 

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Loewenstein,  L.  C,  and  Crissey,  C.  P.     Centrifugal  Pumps *4  50 

Lomax,  J.  W.     Cotton  Spinning lamo,  i  50 

Lord,  R.  T.     Decorative  and  Fancy  Fabrics 8vo,  *3  50 

Loring,  A.  E.     A  Handbook  of  the  Electromagnetic  Telegraph ....  i6mo  0  50 

■ Handbook.     (Science  Series  No.  39.) i6m,  o  50^ 

Lovell,  D.  H.     Practical  Switchwork i2mo,  *i  00 

Low,  D.  A.     Applied  Mechanics  (Elementary) i6mo,       o  80 

Lubschez,  B.  J.     Perspective i2mo,     *i  50 

Lucke,  C.  E.     Gas  Engine  Design 8vo,     *3  00 

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t  hi  Preparation.) 
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Lunge,  G.     Coal-tar  and  Ammonia.     Two  Volumes 8vo,  *i5  00 

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■ Technical  Chemists'  Handbook i2mo,  leather,     *3  50 

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Vol.     I.     In  two  parts Svo,   *i5  00 

Vol.    II.     In  two  parts Svo,   *i8  00 

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The  set  (3  vols.)  complete *48  00 

Luquer,  L.  M.     Minerals  in  Rock  Sections Svo,     *i  s^ 

Macaulay,  J.,  and  Hall,  C.    Modern  Railway  Working,  8  vols 4to, 

Each   volume   separately 3 

Macewen,  H.  A.     Food  Inspection Svo, 

Mackenzie,  N.  F.     Notes  on  Irrigation  Works Svo, 

Mackie,  J.     How  to  Make  a  Woolen  Mill  Pay Svo, 

Mackrow,  C.     Naval  Architect's  and  Shipbuilder's  Pocket-book. 

i6mo,  leather, 
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Malcolm,  C.  W.    Textbook  on  Graphic  Statics Svo,     *3  00 

Malcolm,  H.  W-     Submarine  Telegraph  Cable (In  Press.) 

Mallet,  A.     Compound  Engines.     Trans,  by  R.  R.  Buel.     (Science  Series 

No.  10.) i6mo, 

Mansfield,  A.  N.  Electro-magnets.  (Science  Series  No.  64.)  ...i6mo,  0  50 
Marks,  E.  C.  R.  Construction  of  Cranes  and  Lifting  Machinery  .  i2mo,  *i  50 
Construction  and  Working  of  Pumps i2mo,     *i  50 


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19 


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Manufacture  of  Iron  and  Steel  Tubes i2mo, 

Mechanical  Engineering  Materials i2mo, 

Marks,  G.  C.     Hydraulic  Power  Engineering 8vo, 

Inventions,  Patents  and  Designs i2mo, 

Marlow,  T.  G.     Drying  Machinery  and  Practice 8vo, 

Marsh,  C.  F.     Concise  Treatise  on  Reinforced  Concrete   8vo, 

Reinforced  Concrete  Compression  Member  Diagram.     Mounted  on 

Cloth  Boards *r  50 

Marsh,  C.  F.,  and  Dunn,  W.     Manual  of  Reinforced  Concrete  and  Con- 
crete Block  Construction i6mo,  morocco,     *2  50 

Marshall,  W.  J.,  and  Sankey,H.R.     Gas  Engines.     (Westminster  Series. ) 

8vo,     *2  00 

Martin,  G.     Triumphs  and  Wonders  of  Modern  Chemistry Svo,       *2  00 

Modern  Chemistry  and  Its  Wonders (  /»   Press. ) 

Martin,  N.     Properties  and  Design  of  Reinforced  Concrete i2mo,     *2  50 

Martin,  W.  D.    Hints  to  Engineers i2mo,     *i  00 

Massie,  W.  W.,  and  Underbill,  C.  R.     Wireless  Telegraphy  and  Telephony. 

i2mo,     *i  oo 
Matheson,D.    Australian  Saw-Miller's  Log  and  Timber  Ready  Reckoner. 

i2mo,  leather,       i  50 

Mathot,  R.  E.     Internal  Combustion  Engines Svo,     *6  co 

Maurice,  W.     Electric  Blasting  Apparatus  and  Explosives Svo,     *3  50 

Shot  Firer's  Guide Svo,     *i  50 

Maxwell,     J.     C.       Matter    and  Motion.       (Science    Series  No.  36.1. 

i6mc,     o  50 
Maxwell,  W.  H.,  and  Brown,  J.  T.     Encyclopedia  of  Municipal  and  Sani- 
tary Engineering 4to,  *io  00 

Mayer,  A.  M.     Lecture  Notes  on  Physics Svo, 

Mayer,  C,  and  Slippy,  J.  C.     Telephone  Line  Construction Svo, 

McCullough,  E.     Practical  Surveying i2mo, 

Engineering  Work  in  Cities  and  Towns Svo, 

Reinforced   Concrete    i2mo, 

McCullough,  R.  S.     Mechanical  Theory  of  Heat Svo, 

McGibbon,  W.  C.    Indicator  Diagrams  for  Marine  Engineers Svo, 

Marine  Engineers'  Drawing  Book oblong  4to, 

Mcintosh,  J.  G.     Technology  of  Sugar , Svo, 

Industrial  Alcohol Svo, 

Manufacture  of  Varnishes  and  Kindred  Industries.     Three  Volumes. 

Svo. 

Vol.     I.     Oil  Crushing,  Refining  and  Boiling *3  50 

Vol.    II.     Varnish  Materials  and  Oil  Varnish  Making *4  00 

Vol.  III.     Spirit  Varnishes  and  Materials *4  50 

McKnight,  J.  D.,  and  Brown,  A.  W.     Marine  Multitubular  Boilers *i  50 

McMaster,  J.  B.     Bridge  and  Tunnel  Centres.     (Science  Series  No.  20.) 

i6mo,       o  50 

McMechen,  F.  L.     Tests  for  Ores,  Minerals  and  Metals i2mo,     *i  00 

McPherson,  J.  A.     Water-works  Distribution Svo,       2  50 

Meade,  R.  K.    Design  and  Equipment  of  Small  Chemical  Laboratories, 

Svo, 
Melick,  C.  W.     Dairy  Laboratory  Guide i2mo,     *i  25 


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20        D-  VAN  NOSTRAND  CO.'S  SHORT  TITLE  CATALOG 

Mensch,  L.  J.     Reinforced  Concrete  Pocket  Book i6mo,  leather,     *4  oo 

Merck,  E.     Chemical  Reagents ;   Their  Purity  and  Tests.     Trans,   by 

H.  E.   Schenck 8vo,      i  oo 

.  Merivale,  J.  H.     Notes  and  Formulae  for  Mining  Students lamo,      i  50 

Merritt,  Wm.  H.     Field  Testing  for  Gold  and  Silver i6mo,  leather,      i  50 

Meyer,  J.  G.  A.,  and  Pecker,  C.  G.     Mechanical  Drawing  and  Machine 

Design 4to,       5  00 

Mierzinski,  S.     Waterproofing  of  Fabrics.     Trans,  by  A.  Morris  and  H. 

Robson 8vo,     *2  5a 

Miessner,  B.  F.     Radio  Dynamics (In  Press.) 

Miller,  G,  A.     Determinants.     (Science  Series  No   105.) i6mo, 

Milroy,  M.  E.  W.     Home  Lace-making i2mo,     *i  00 

Mitchell,  C.  A.     Mineral  and  Aerated  Waters 8vo,     *3  oa 

Mitchell,  C.  A.,  and  Prideaux,  R.  M.     Fibres  Used  in  Texdie  and  Allied 

Industries 8vo,     *3  co 

Mitchell,  C.  F.,  and  G.  A.     Building  Construction  and  Drawing.     i2mo. 

Elementary  Course *i  50 

Advanced  Course *2  50 

Monckton,  C.  C.  F.     Radiotelegraphy.     (Westminster  Series.) Svo,  *2  00 

Monteverde,  R.  D.     Vest  Pocket  Glossary  of  English-Spanish,  Spanish- 
English  Technical  Terms 64mo,  leather,  *i  oa 

Montgomery,  J.  H.     Electric  Wiring  Specifications i6mo,  *i  00 

Moore,  E.  C.  S.     New  Tables  for  the  Complete  Solution  of  Ganguillet  and 

Kutter's  Formula Svo,     *5  oa 

Morecroft,  J.  H.,  and  Hehre,  F.  W.     Short  Course  in  Electrical  Testing. 

Svo, 

Morgan,  A.  P.     Wireless  Telegraph  Apparatus  for  Amateurs i2mo, 

Moses,  A.  J.     The  Characters  of  Crystals Svo, 

and  Parsons,  C.  L.     Elements  of  Mineralogy Svo, 

Moss,  S.A.  Elements  of  Gas  Engine  Design. (Science  Series  No.i2i.)i6mo, 

The  Lay-out  of  Corliss  Valve  Gears.     (Science  Series  No.  ii9.)i6mo, 

Mulford,  A.  C.     Boundaries  and  Landmarks i2mo, 

Mullin,  J.  P.     Modem  Moulding  and  Pattern-making i2mo, 

Munby,  A.  E.     Chemistry  and  Physics  of  Building  Materials.     (West- 
minster Series.) Svo, 

Murphy,  J.  G.     Practical  Mining i6mo, 

Murphyj  W.  S.    Textile  Industries.     Eight  Volumes *2o 

Sold  separately,  each, 
Murray,  J.  A.     Soils  and  Manures.     (Westminster  Series.) Svo, 

Naquet,  A.     Legal  Chemistry i2mo, 

Nasmith,  J.     The  Student's  Cotton  Spinning Svo, 

Recent  Cotton  Mill  Construction i2mo, 

Neave,  G.  B.,  and  Heilbron,  I,  M.     Identification  of  Organic  Compounds. 

i2mo, 

Neilson,  R.  M.     Aeroplane  Patents Svo, 

Nerz,  F.     Searchlights.     Trans,  by  C.  Rodgers Svo, 

Neuberger,  H.,  and  Noalhat,  H.     Technology  of  Petroleum.     Trans,  by 

J.  G.  Mcintosh Svo, 

Newall,  J.  W.     Drawing,  Sizing  and  Cutting  Bevel-gears Svo, 


*I 

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50 

0 

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0 

50 

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2 

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3 

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2 

00 

*i 

25 

*2 

oa 

*3 

00 

10 

00 

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50 

D.  VAN  NOSTRAXD  CO.'S  SHORT  TITLE  CATALOG        21 

INewbeging,  T.     Handbook  for  Gas  Engineers  and  Managers 8vo,  *6  50 

Jfewton,  G.  J.     Underground  Distribution  Systems (In  Press. ) 

Nicol,  G.     Ship  Construction  and  Calculations 8vo,  *4  50 

Nipher,  F.  E.     Theory  of  Magnetic  Measurements i2mo,  i  00 

]yfisbet,  H.     Grammar  ot  Textile  Design 8vo,  *3  00 

Kolan,  H.     The  Telescope.     (Science  Series  No.  51.) i6mo,  0  50 

Noll,  A.     How  to  Wire  Buildings i2mo,  1  50 

North,  H.  B.    Laboratory  Experiments  in  General  Chemistry lamo,  ^i  00 

Nugent,  E.     Treatise  on  Optics izmo,  r  50 

O'Connor,  H.     The  Gas  Engineer's  Pocketbook i2mo,  leather,  3  50 

Petrol  Air  Gas i2mo,  *o  75 

Ohm,  G.  S.,  and  Lockwood,  T.  D.     Galvanic  Circuit.     Translated  by 

William  Francis.     (Science  Series  No.  102.) i6mo,  o  50 

Olsen,  J.  C.     Text-book  of  Quantitative  Chemical  Analysis 8vo,  *4  00 

Olsson,  A.     Motor  Control,  in  Turret  Turning  and  Gun  Elevating.     (U.  S. 

Navy  Electrical  Series,  No.  i.) i2mo,  paper,  *o  50 

Ormsby,  M.  T.  M.     Surveying i2mo,  i  50 

Oudin,  M.  A.     Standard  Polyphase  Apparatus  and  Systems 8vo,  *3  00 

Owen,   D.     Recent   Physical   Research 8vo,  '  i  50 

Pakes,  W.  C.  C,  and  Nankivell,  A.  T.     The  Science  of  Hygiene  .   Svo,  *i  75 

Palaz,  A.     Industrial  Photometry.     Trans,  by  G.  W.  Patterson,  Jr.  .  Svo,  *4  00 

Pamely,  C.     Colliery  Manager's  Handbook Svo,  *io  00 

Parker,  P.  A.  M.     The  Control  of  Water Svo,  *5  00 

Parr,  G.  D.  A.     Electrical  Engineering  Measuring  Instruments.  ..  .Svo,  "^3  50 

Parry,  E.  J.     Chemistry  of  Essential  Oils  and  Artificial  Perfumes.  .   Svo,  *5  00 

Foods  and  Drugs.     Two  Volumes Svo, 

Vol.    I.     Chemical  and  Microscopical  Analysis  of  Foods  and  Drugs.  *7  5° 

Vol.  II.     Sale  of  Food  and  Drugs  Act *3  00 

and  Coste,  J.   H.     Chemistry   of   Pigments Svo,  *4  50 

Parry,  L.     Notes  on  Alloys Svo,  *3  00 

Metalliferous  Wastes    Svo,  *2  00 

Analysis  of  Ashes  and  Alloys Svo,  *2  00 

Parry,  L.  A.     Risk  and  Dangers  of  Various  Occupations Svo,  *3  00 

Parshall,  H.  F.,  and  Hobart,  H.  M.     Armature  Windings 4to,  *7  50 

Electric  Railway  Engineering 4to,  *io  00 

Parsons,  J.  L.     Land  Drainage Svo,  *i  50 

Parsons,  S.  J.     Malleable  Cast  Iron Svo,  *2  50 

Partington,  J.  R,     Higher  Mathematics  for  Chemical  Students.  .  i2mo,  *2  00 

Textbook  of  Thermodynamics Svo,  *4  00 

Passmore,  A.  C.     Technical  Terms  Used  in  Architecture Svo,  *3  50 

Patchell,  W.  H.     Electric  Power  in  Mines Svo,  *4  00 

Paterson,  G.  W.  L.     Wiring  Calculations i2mo,  *2  00 

Electric  Mine  Signalling  Installations i2mo,  *i  50 

Patterson,  D.     The  Color  Printing  of  Carpet  Yarns Svo,  *3  50 

Color  Matching  on  Textiles Svo,  *3  00 

Textile   Color  Mixing Svo,  *3  00 

Paulding,  C.  P.     Condensation  of  Steam  in  Covered  and  Bare  Pipes.  .Svo,  *2  00 
Transmission  of  Heat  through  Cold-storage  Insulation r2mo,  *r  00 


22        D.  VAN  NOSTRAND  CO.'S  SHORT  TITLE  CATALOG 

Payne,   D.   W.     Iron  Founders'   Handbook {In   Press.) 

Peckham,  S.  F.     Solid  Bitumens 8vo, 

Peddle,  R.  A.     Engineering  and  Metallurgical  Books i2mo, 

Peiice,  B.     System  of  Analytic  Mechanics 4to, 

Pendred,  V.     The  Railway  Locomotive.     (Westminster  Series.) 8vo, 

Perkin,  F.  M.    Practical  Methods  of  Inorganic  Chemistry i2mo, 

and  Jaggers,  E.  M.     Elementary  Chemistry lamo, 

Perrigo,  0.  E.     Change  Gear  Devices 8vo, 

Perrine,  F.  A.  C.     Conductors  for  Electrical  Distribution 8vo, 

Petit,  G.     White  Lead  and  Zinc  White  Paints. Svo, 

Petit,  R.     How  to  Build  an  Aeroplane.     Trans,  by  T.  O'B.  Hubbard,  and 

J.  H.  Ledeboer Svo, 

Pettit,  Lieut.  J.  S.     Graphic  Processes.     (Science  Series  No.  76.) . . .  i6mo, 
Philbrick,  P.  H.     Beams  and  Girders.     (Science  Series  No.  88.) . .  .  i6mo, 

Phillips,  J.     Gold  Assaying Svo, 

Dangerous  Goods Svo, 

Phin,  J.     Seven  Follies  of  Science 12  mo, 

Pickworth,  C.  N.     The  Indicator  Handbook.     Two  Volumes.  .  i2mo,  each, 

Logarithms  for  Beginners 12  mo.  boards, 

The  Slide  Rule 12  mo, 

Plattner's  Manual  of  Blow-pipe  Analysis.    Eighth  Edition,  revised.    Trans. 

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Plympton,  G.  W.    The  Aneroid  Barometer.    (Science  Series  No.  35.)    16 mo, 

How  to  become  an  Engineer.      (Science  Series  No.  100.) i6mo, 

Van  Nostrand's  Table  Book.      (Science  Series  No.  104.) i6mo, 

Pochet,  M.  L.     Steam  Injectors.     Translated  from  the  French.     (Science 

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Pocket  Logarithms  to  Four  Places.     (Science  Series  No.  65.) 16  mo, 

leather, 

PoUeyn,  F.     Dressings  and  Finishings  for  Textile  Fabrics Svo, 

Pope,  F.  G.     Organic  Chemistry i2mo, 

Pope,  F.  L.     Modern  Practice  of  the  Electric  Telegraph Svo, 

Popplewell,  W.   C.     Prevention  of   Smoke Svo, 

Strength  of  Materials .  Svo, 

Porritt,   B.    D.     The   Chemistry    of    Rubber.      (Chemical   Monographs, 

No.   3.) i2mo, 

Porter,  J.  R.     Helicopter  Flying  Machine 12  mo. 

Potts,  H.  E.     Chemistry  of  the  Rubber  Industry.     (Outlines  of  Indus- 
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Practical  Compounding  of  Oils,  Tallow  and  Grease Svo, 

Pratt,  K.    Boiler  Draught lamo, 

High   Speed   Steam   Engines Svo, 

Pray,  T.,  Jr.     Twenty  Years  with  the  Indicator Svo, 

Steam  Tables  and  Engine  Constant Svo, 

Prelini,  C.     Earth  and  Rock  Excavation Svo, 

Graphical  Determination  of  Earth  Slopes Svo, 

• Tunneling.    New  Edition Svo, 

■ Dredging.    A  Practical  Treatise Svo, 

Prescott,  A.  B.     Organic  Analysis Svo, 

Prescott,  A.  B.,  and  Johnson,  0.  C.     Qualitative  Chemical  Analysis.  .   Svo, 


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D.  VAN  NOSTRAND  CO.'S  SHORT  TITLE  CATALOG       23 

Prescott,  A.  B.,  and  Sullivan,  E.  C.     First  Book  in  Qualitative  Chemistry. 

i2mo, 

Prideaux,  E.  B.  R.     Problems  in  Physical  Chemistry 8vo, 

Primrose,  G.  S.  C.     Zinc.     (  Metallurgy  Series. ) (In  Press. ) 

Pullen,   W.   W.  F.     Application  of  Graphic  Methods  to  the  Design  of 

Structures i2mo, 

Injectors:  Theory,  Construction  and  Working i2mo, 

Indicator  Diagrams    8vo, 

Engine   Testing    8vo, 

Pulsifer,  W.  H.     Notes  for  a  History  of  Lead 8vo, 

Putsch,  A.     Gas  and  Coal-dust  Firing. 8vo, 

Pynchon,  T.  R.     Introduction  to  Chemical  Physics Svo, 

Rafter  G.  W.     Mechanics  of  Ventilation.     (Science  Series  No.  33.) .  i6mo, 

Potable  Water.     (  Science  Series  No.  103.) i6rao, 

Treatment  of  Septic  Sewage.     (Science  Series  No.  118. » .  . .  i6mo, 

Rafter,  G.  W.,  and  Baker,  M.  N.     Sewage  Disposal  in  the  United  States. 

4to, 

Raikes,  H,  P.     Sewage  Disposal  Works Svo, 

Randall,  P.  M.     Quartz  Operator's  Handbook. i2mo, 

Randau,  P.     Enamels  and  Enamelling Svo, 

Rankine,  W.  J.  M.     Applied  Mechanics Svo, 

Civil  Engineering Svo, 

Machinery  and  Millwork Svo, 

—  ^  The  Steam-engine  and  Other  Prime  Movers .Svo, 

Rankine,  W,  J.  M.,  and  Bamber,  E.  F.     A  Mechanical  Text- book. .  .   Svo, 
Raphael,  F.  C.     Localization  of  Faults  in  Electric  Light  and  Power  Mains. 

Svo, 

Rasch,  E.    Electric  Arc  Phenomena.    Trans,  by  K.  Tornberg 8vo, 

Rathbone,  R.  L,  B.     Simple  Jewellery Svo, 

Rateau,  A,     Flow  of  Steam  through  Nozzles  and  Orifices.     Trans,  by  H. 

B.  Brydon Svo 

Rausenberger,  F.     The  Theory  of  the  Recoil  of  Guns Svo, 

Rautenstrauch,  W.     Notes  on  the  Elements  of  Machine  Design. Svo,  boards, 
Rautenstrauch,  W,,  and  Williams,  J.  T.     Machine  Drafting  and  Empirical 

Design. 

Part   I.  Machine  Drafting Svo,     *i   25 

Part  II.  Empirical  Design (In  Preparation.) 

Raymond,  E.  B.     Alternating  Current  Engineering i2mo,     *2  50 

Rayner,  H.     Silk  Throwing  and  Waste  Silk  Spinning Svo,     *2  50 

Recipes  for  the  Color,  Paint,  Varnish,  Oil,  Soap  and  Drysaltery  Trades .  Svo,     *3  50 

Recipes  for  Flint  Glass  Making i2mo,     *4  50 

Redfem,  J.  B.,  and  Savin,  J.     Bells,  Telephones  (Installation  Manuals 

Series.) i6mo,     *o  50 

Redgrove,  H.  S.     Experimental  Mensuration lamo,     *i  25 

Redwood,  B.     Petroleum.     (Science  Series  No.  92.) i6mo,  o  50 

Reed,  S.    Turbines  Applied  to  Marine  Propulsion *5  00 

Reed's  Engineers'  Handbook Svo,  *5  00 

Key  to  the  Nineteenth  Edition  of  Reed's  Engineers'  Handbook.   Svo,  *3  00 

Useful  Hints  to  Sea-going  Engineers i2mo,  i  50 

• Guide  to  the  Use  of  the  Slide  Valve i2mo,  *i  60 


•I 

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'2 

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24       D-  VAN  NOSTRAND  CO.'S  SHORT  TITLE  CATALOG 

Reid,  E.  E.    Introduction  to  Research  in  Organic  Chemistry.  {In  Press.) 

Reid,  H.  A.     Concrete  and  Reinforced  Concrete  Construction 8vo,     *5  oo 

Reinhardt,  C.  W.     Lettering  for  Draftsmen,  Engineers,  and  Students. 

oblong  4to,  boards,       i  oo 

The  Technic  of  Mechanical  Drafting oblong  4to,  boards,     *i  oo 

Reiser,  F.     Hardening  and  Tempering  of  Steel.     Trans,  by  A.  Morris  and 

H.  Robson ^ i2mo,     *2  50 

Reiser,  N.     Faults  in  the  Manufacture  of  Woolen  Goods.     Trans,  by  A. 

Morris  and  H.  Robson 8vo,     *2  50 

Spinning  and  Weaving  Calculations 8vo,     *5  00 

Renwick,  W.  G.     Marble  and  Marble  Working 8vo,       5  00 

Rouleaux,  F.     The  Constructor.     Trans,  by  H.  H.  Suplee 4to,     *4  00 

Reuterdahl,  A.    Theory  and  Design  of  Reinforced  Concrete  Arches. 8vo,     *2  00 
Reynolds,   0.,   and  Idell,   F.   E.     Triple   Expansion   Engines.     (Science 

Series  No.  99.) i6mo,       o  50 

Rhead,  G.  F.     Simple  Structural  Woodwork i2mo,     *i  00 

Rhodes,  H.  J.     Art  of  Lithography 8vo,      3  50 

Rice,  J.  M.,  and  Johnson,  W.  W.     A  New  Method  of  Obtaining  the  Differ- 
ential of  Functions i2mo,       0  50 

Richards,  W.  A.     Forging  of  Iron  and  Steel ....(/»  Press.) 

Richards,  W.  A.,  and  North,  H.  B.    Manual  of  Cement  Testing. .  .  .  i2mo, 

Richardson,  J.     The  Modern  Steam  Engine 8vo, 

Richardson,  S.  S.     Magnetism  and  Electricity lamo, 

Rideal,  S.     Glue  and  Glue  Testing 8vo, 

Rimmer,  E.  J.    Boiler  Explosions,  Collapses  and  Mishaps 8vo, 

Rings,  F.     Concrete  in  Theory  and  Practice i2mo, 

Reinforced  Concrete  Bridges 4to, 

Ripper,  W.     Course  of  Instruction  in  Machine  Drawing folio, 

Roberts,  F.  C.     Figure  of  the  Earth.     (Science  Series  No.  79.) i6mo, 

Roberts,  J.,  Jr.     Laboratory  Work  in  Electrical  Engineering 8vo, 

Robertson,  L.  S.     Water-tube  Boilers Svo, 

Robinson,  J.  B.     Architectural  Composition Svo, 

Robinson,  S.  W.     Practical  Treatise  on  the  Teeth  of  Wheels.     (Science 

Series  No.  24.) i6mo, 

Railroad  Economics.     (Science  Series  No.  59.) i6mo, 

Wrought  Iron  Bridge  Members.     (Science  Series  No.  60.) i6mo, 

Robson,  J.  H.     Machine  Drawing  and   Sketching Svo, 

Roebling,  J.  A.     Long  and  Short  Span  Railway  Bridges folio, 

Rogers,  A.     A  Laboratory  Guide  of  Industrial  Chemistry i2mo, 

Rogers,  A.     Industrial  Chemistry Svo, 

Rogers,  F.  Magnetism  of  Iron  Vessels.  (Science  Series  No.  30.) .  i6mo, 
Rohland,  P.     Colloidal  and  Crystalloidal  State  of  Matter.     Trans,  by 

W.  J.  Britland  and  H.  E.  Potts i2mo, 

Rollins,  W.     Notes  on  X-Light 8vo, 

Rollinson,  C.     Alphabets Oblong,  i2mo. 

Rose,  J.     The  Pattern-makers'  Assistant 8vo, 

~ —  Key  to  Engines  and  Engine-running i2mo, 

Rose,  T.  K.     The  Precious  Metals.     (Westminster  Series.) Svo, 

Rosenhain,  W.     Glass  Manufacture.     (Westminster  Series.) Svo. 

Physical   Metallurgy,   An  Introduction  to.      (Metallurgy   Series.) 

Svo,    On  Press.) 


*I 

50 

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*2 

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*2 

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0 

50 

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50 

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00 

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00 

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50 

*i 

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*5 

00 

*i 

00 

2 

50 

2 

50 

*2 

00 

*2 

00 

D.  VAN  NOSTRAND  CO.'S  SHORT  TITLE  CATALOG        25 

Ross,  W.  A.     Blowpipe  in  Chemistry  and  Metallurgy i2mo,  *2  00 

Roth.     Physical  Chemistry 8vo,  *2  00 

Rothery,  G.  C,  and  Edmonds,  H.  0.     The  Modern   Laundry,  2   vols., 

4to,  half  leather,  *i2  00 

Rouillion,  L.     The  Economics  of  Manual  Training 8vo,  2  00 

Rowan,  F.  J.     Practical  Physics  of  the  Modern  Steam-boiler 8vo,  *3  00 

and    Idell,    F.    E.     Boiler   Incrustation   and    Corrosion.      ( Science 

Series   No.   27.) i6mo,  o  50 

Roxburgh,  W.    General  Foundry  Practice.     (Westminster  Series. )  .8vo,  '■'%  00 

Ruhmer,  E.     Wireless  Telephony.     Trans,  by  J.  Erskine-Murray .  .8vo,  *3  50 

Russell,  A.     Theory  of  Electric  Cables  and  Networks Svo,  *3  00 

Sabine,  R.     History  and  Progress  of  the  Electric  Telegraph i2mo,  i  25 

Sanford,  P.  G.     Nitro-explosives Svo,  *4  00 

Saunders,  C.  H.     Handbook  of  Practical  Mechanics i6mo,  i  00 

leather,  i  25 

Bayers,  H.  M.     Brakes  for  Tram  Cars Svo,  *i  25 

Scheele,  C.  W.     Chemical  Essays Svo,  *2  00 

Scheithauer,    W.     Shale    Oils    and    Tars Svo,  *3  5o 

Schellen,  H.     Magneto-electric  and  Dynamo-electric  Machines  .       Svo,  5  00 

Scherer,  R.     Casein.     Trans,  by  C.  Salter Svo,  *3  00 

Schidrowitz,  P.     Rubber,  Its  Production  and  Industrial  Uses Svo,  *5  00 

Schindler,  K.     Iron  and  Steel  Construction  Works i2mo,  *i  25 

Schmall,  C.  N.     First  Course  in  Analytic  Geometry,  Plane  and  Solid. 

i2mo,  half  leather,  *i  75 

Schmall,  C.  N.,  and  Shack,  S.  M.     Elements  of  Plane  Geometry. ..  i2mo,  *i   25 

Schm.eer,  L.     Flow  of  Water Svo,  *3  or 

Schumann,  F.    A  Manual  of  Heating  and  Ventilation.  ..  .i2mo,  leather,  i  50 

Schwarz,  E.  H.  L.     Causal  Geology Svo,  *2  50 

Schweizer,  V.     Distillation  of  Resins Svo,  *3  50 

Scott,  W.  W.     Qualitative  Analysis.     A  Laboratory  Manual Svo,  *i  50 

Scribner,  J.  M.     Engineers'  and  Mechanics'  Companion.  .  i6mo,  leather,  i  50 
Scudder,    H.      Electrical    Conductivity    and    Ionization    Constants    of 

Organic  Compounds Svo,  *3  00 

Searle,  A.  B.     Modern   Brickraaking Svo,  *5  00 

Cement,   Concrete  and    Bricks Svo,  "=3  00 

Searle,     G.     M.       "Sumners'     Method."       Condensed     and     Improved. 

(Science   Series   No.    124.) i6mo,  o  50 

Seaton,  A.  E.     Manual   of  Marine  Engineering Svo  8  00 

Seaton,  A.  E.,  and  Rounthwaite,  H.  M.     Pocket-book  of  Marine  Engi- 
neering  i6mo,  leather,  3  50 

SeeJigmann,  T.,  Torrilhon,  G.  L.,  and  Falconnet,  H.    India  Rubber  and 

Gutta   Percha.     Trans,   by  J.  G.   Mcintosh Svo,  *5  00 

Seidell,  A.    Solubilities  of  Inorganic  and  Organic  Substances Svo,  *3  00 

Seligman,    R.     Aluminum.      (Metallurgy    Series.) (In  Press.) 

Sellew,   W.   H.     Steel   Rails 4to,  *i2  50 

Railway   Maintenance    i  fn    Pri'ss. ) 

Senter,  G.     Outlines  of  Physical  Chemistry i2mo,  *i  75 

■ Text-book  of  Inorganic  Chemistry lamo,  *i  75 


2G        D.  VAN  NOSTRAND  CO.'S  SHORT  TITLE  CATALOG 

Sever,  G.  F.     Electric  Engineering  Experiments 8vo,  boards, 

Sever,  G.  F.,  and  Townsend,  F.    Laboratory  and  Factory  Tests  in  Elec- 
trical Engineering Svo, 

Sewall,  C.  H.    Wireless  Telegraphy Svo, 

Lessons   in   Telegraphy lamo, 

Sewell,  T.     The  Construction  of  Dynamos Svo, 

Sexton,  A.  H.     Fuel  and  Refractory  Materials i2mo, 

Chemistry  of  the  Materials  of  Engineering i2mo, 

Alloys  (Non-Ferrous  ) Svo, 

■ The  Metallurgy  of  Iron  and  Steel Svo, 

Seymour,  A.     Modern  Printing  Inks Svo, 

Shaw,  Henry  S.  H.     Mechanical  Integrators.    (Science  Series  No.  83.) 

i6mo, 

Shav/,  S.     History  of  the  Staffordshire  Potteries Svo, 

Chemistry  of  Compounds  Used  in  Porcelain  Manufacture.  ..  .Svo, 

Shaw,  V/.  N.     Forecasting   Weather Svo, 

Sheldon,  S.,  and  Hausmann,  E.    Direct  Current  Machines i2mo, 

Alternating   Current   Machines lamo, 

Sheldon,  S.,  and  Hausmann,  E.     Electric  Traction  and  Transmission 

Engineering i2mo. 

Shields,  J.  E.     Notes  on  Engineering  Construction i2mo, 

Shreve,  S.  H.     Strength  of  Bridges  and  Roofs Svo, 

vShunk,  W.  F.     The  Field   Engineer i2mo,  morocco, 

Simmons,  W.  H.,  and  Appleton,  H.  A.    Handbook  of  Soap  Manufacture, 

Svo, 

Simmons,  W.  H.,  and  Mitchell,  C.  A.     Edible  Fats  and  Oils Svo, 

Simpson,  G.     The   Naval  Constructor i2mo,  morocco, 

Simpson,  W.     Foundations Svo.    (  /;;  Press.) 

Sinclair,  A.     Development  of  the  Locomotive  Engine. .  .  Svo,  half  leather, 

Sindall,  R.  W.,  and  Bacon,  W.  N.     The  Testing  of  Wood  Pulp Svo, 

Sindall,  R.  W.    Manufacture  of  Paper.     (  Westminster  Series.) .  . .  .Svo, 

Sloane,  T.  O'C.     Elementary  Electrical  Calculations lamo, 

Smallwood,  J.  C.     Mechanical  Laboratory  Methods.     (Van  Nostrand's 

Textbooks.)     i2mo,    leather. 

Smith,  C.  A.  M.     Handbook  of  Testing,  MATERIALS Svo, 

Smith,  C.  A.  M.,  and  Warren,  A.  G.     New  Steam  Tables Svo, 

Smith,  C.  F.     Practical  Alternating  Currents  and  Testing Svo, 

Practical  Testing  of  Dynamos  and  Motors Svo, 

Smith,   F.   A.     Railway   Curves i2mo, 

Standard    Turnounts    on   American    Railroads i2mo, 

■ — —  Maintenance    of   Way   Standards i2mo. 

Smith,  F.  E.     Handbook  of  General  Instruction  for  Mechanics  .  .  .  i2mo, 

Smith,  K.  G.     Minerals  and  the  Microscope izmo. 

Smith,  J.  C.     Manufacture  of  Paint Svo, 

Smith,  R.  H.     Principles  of  Machine  Work i2mo, 

■ Elements  of  Machine  Work i2mo. 

Smith,  W.     Chemistry  of  Hat  Manufacturing lamo, 

Snell,    A.    T.     Electric    Motive  Power Svo, 

Snow,  W.  G.     Pocketbook  of  Steam  Heating  and  Ventilation.    (In  Press.) 


^2 

50 

*2 

00 

*I 

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00 

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50 

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50 

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25 

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00 

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50 

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25 

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50 

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00 

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00 

*3 

00 

*4 

00 

D.  VAN  NOSTRAND  CO.'S  SHORT  TITLE  CATALOG  27 

Saow,  W.  G.,  and  Nolan,  T,     Ventilation  cf  Buildings.     (Science  Series 

No.  5.) i6nio,  0  50 

Soddy,  F.     Radioactivity 8vo,  *3  00 

Solomon,  M.     Electric  Lamps.     (Westminster  Series.) 8vo,  *2  00 

Somerscales,  A.  N.     Mechanics  for  Marine  Engineers i2mo,  *i  50 

Mechanical  and  Marine  Engineering  Science 8vo,  *5  00 

Sothern,  J.  W.     The  Marine  Steam  Turbine 8vo,  *5  00 

Verbal  Notes  and  Sketches  for  Marine  Engineers 8vo,  *5  00 

Sothern,   J.    W.,   and    Sothern,    R.    M.     Elementary   Mathematics    for 

Marine  Engineers i2mo,  *i  00 

Simple  Problems  in  Marine  Engineering  Design lamo,  *i  00 

Southcombe,  J.  E.     Chemistry  of  the  Oil  Industries.     (Outlines  of  In- 
dustrial Chemistry.] • 8vo,  *3  00 

Soxhlet,  D.  H.     Dyeing  and  Staining  Marble.     Trans,  by  A.  Morris  and 

H.  Robson Svo,  *2  50 

Spang,  H.  W.     A  Practical  Treatise  on  Lightning  Protection             i2mo,  i  00 
Spangenburg,   L.     Fatigue   of   Metals.     Translated  by   S.    H.    Shreve. 

(Science  Series  No.  23.) i6mo,  c  50 

Specht,  G.  J.,  Hardy,  A.  S.,  McMaster,  J.  B.,  and  Walling.    Topographical 

Surveying.     (Science  Series  No.  72.) i6mo,  o  50 

Spencer,  A.  S.     Design  of  Steel-Framed  Sheds Svo,  *4  00 

Speyers,  C.  L.     Text-book  of  Physical  Chemistry Svo,  *2  25 

Spiegel,  L.    Chemical  Constitution  and  Physiological  Action.     (  Trans. 

by  C.  Luedeking  and  A.  C.  Boylston. ) i  25 

Sprague,    E.    H.     Hydraulics lamo,  i  25 

Stahl,  A.  W.     Transmission  of  Power.     (Science  Series  No.  28.)  ,  i6mo, 

Stahl,  A.  W.,  and  Woods,  A.  T.     Elementary  Mechanism i2mo,  *2  00 

Staley,  C,  and  Pierson,  G.  S.     The  Separate  System  of  Sewerage..   Svo,  *3  00 

Standage,  H.  C.     Leatherworkers'  Manual Svo,  *3  50 

Sealing  Waxes,  Wafers,  and  Other  Adhesives Svo,  *2  00 

Agglutinants  of  all  Kinds  for  all  Purposes i2mo,  *3  50 

Stanley,  H.     Practical  Applied  Physics (/;i  Press.  < 

Stansbie,  J.  H.     Iron  and  Steel.     (Westminster  Series.) Svo,  *2  od 

Steadman,   F.   M.     Unit  Photography i2n:o,  *2  00 

Stecher,  G.  E.     Cork.     Its  Origin  and  Industrial  Uses :2mo,  i  00 

Steinman,  D.  B.     Suspension  Bridges  and  Cantilevers.     (Science  Series 

No.  127.) o  50 

Melan's   Steel   Arches   and   Suspension  Bridges Svo,  ^^3  00 

Stevens,  H.  P.     Paper  Mill  Chemist i6mo,  *2  50 

Stevens,  J.   S.     Theory  of  Measurements i2mo,  *i  25 

Stevenson,  J.  L.     Blast-Fumace  Calculations i2mo,  leather,  *2  00 

Stewart,  G.     Modem  Steam  Traps i2mo,  *i  25 

Stiles,  A.     Tables  for  Field  Engineers i2mo,  i  00 

Stodola,  A,     Steam  Turbines.    Trans,  by  L.  C.  Loewenstein Svo,  *5  00 

Stone,  H.     The  Timbers  of  Commerce 8vo,  3  50 

Stopes,  M.     Ancient  Plants 8vo,  *2  00 

The  Study  of  Plant  Life 8vo,  *2  00 

Stumpf,  Prof.     Una-Flow  of  Steam  Engine 4to,  *3  50 

Sudborough,  J.  J.,  and  James,T.  C.    Practical  Organic  Chemistry.  i2mo,  *2  00 

Sufl^g,  E.  R.     Treatise  on  the  Art  of  Glass  Painting Svo,  *3  50 

Sur,  F.  J.  S.     Oil  Prospecting  and  Extracting Svo,  *i  00 


28        D-  VAN  NOSTRAND  CO.'S  SHORT  TITLE  CATALOG 

Swan,  K.     Patents,  Designs  and  Trade  Marks.     (Westminster  Series.). 

8vo,     *2  oo 
Swinburne,  J.,  Wordingham,  C.  H.,  and  Martin,  T.  C.     Electric  Currents. 

(Science  Series  No.  109.) i6mo,       0  50 

Swoope,  C.  W.     Lessons  in  Practical  Electricity lamo,     *2  00 

Tailfer,  L.     Bleaching  Linen  and  Cotton  Yam  and  Fabrics 8vo,     *5  oa 

Tate,  J.  S.     Surcharged  and  Different  Forms  of  Retaining-walls.    !  Science 

Series  No.  7.) i6mo,      o  5o> 

Taylor,  F.  N.     Small  Water  Supplies i2mo,     '2  00 

. Masonry   in   Civil   Engineering 8vo,     *2  50 

Taylor,  T.  U.     Surveyor's  Handbook i2mo,  leather,     *2  00 

• Backbone   of   Perspective ^ lamo,     =*i  00 

Taylor,   W.   P.     Practical   Cement   Testing 8vo,    *3  00 

Templeton,  W.     Practical  Mechanic's  Workshop  Companion. 

i2mo,  morocco,       2  00 
Tenney,    E.    H.      Test    Methods    for    Steam    Power    Plants.       (Van 

Nostrand's  Textbooks.^     i2mo,     *2  50 

Terry,  H.L.     India  Rubber  and  its  Manufacture.     (Westminster  Series.) 

8vo,     *2  00 
Thayer,  H.  R.     Structural  Design.     Svo. 

Vol.     I.     Elements  of  Structural  Design *2  00 

Vol.    II.     Design  of  Simple   Structures *4  00 

Vol.  III.     Design  of  Advanced  Structures {In  Preparation.) 

Foundations  and   Masonry {In   Preparation.) 

Thiess,  J.  B.,  and  Joy,  G.  A.     Toll  Telephone  Practice Svo,     *3  50 

Thom,  C,  and  Jones,  W.  H.     Telegraphic  Connections..  .  .oblong,  i2mo,      i  50 

Thomas,  C.  W.     Paper-makers'  Handbook {In  Pre.ss.) 

Thompson,  A.  B.     Oil  Fields  of  Russia 4to,     *7  50 

Thompson,  S.  P.     Dynamo  Electric  Machines.     (Science  Series  No.  75.) 

i6mo, 

Thompson,  W.  P.     Handbook  of  Patent  Law  of  All  Countries i6mo, 

Thomson,  G.  S.     Milk  and  Cream  Testing i2mo, 

Modem  Sanitary  Engineering,  House  Drainage,  etc Svo, 

Thornley,  T.     Cotton  Combing  Machines Svo, 

Cotton  Waste Svo, 

■ Cotton  Spinning.     Svo. 

First  Year 

Second   Year 

Third  Year 

Thurso,  J.  W.     Modem  Turbine  Practice Svo, 

Tidy,  C.  Meymott.     Treatment  of  Sewage.     (Science  Series  No.  94.)i6mo, 
Tillmans,    J.     Water    Purification    and    Sewage    Disposal.     Trans,    by 

Hugh  S.  Taylor 8vo, 

Tinney,  W.  H.     Gold-mining  Machinery Svc, 

Titherley,  A.  W.     Laboratory  Course  of  Organic  Chemistry Svo, 

Toch,  M.     Chemistry  and  Technology  of  Mixed  Paints Svo, 

Materials  for  Permanent  Painting i2mo, 

Chemistry  and  Technology  of  Mixed   Paints (In   Press.) 

Tod,  J.,   and   McGibbon,   W.  C.     Marine    Engineers'    Board   of  Trade 

Examinations 8vo,    *i  50 


0 

50 

I 

50 

°I 

75 

'3 

00 

'3 

00 

'3 

00 

'1 

50 

'2 

50 

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0 

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"3 

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"2 

00 

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00 

D.  VAX  NOSTRAND  CO.'S  SHORT  TITLE  CATALOG 


29 


Todd,  J.,  and  Whall,  W.  B.     Practical  Seamanship 8vo,  *7  50 

Tonge,  J.     Coal.     (Westminster  Series.) 8vo,  *2  00 

Townsend,  F.     Alternating  Current  Engineering 8vo,  boards,  *o  75 

Townsend,  J.     Ionization  of  Gases  by  Collision. 8vo,  *i   25 

Transactions  of  the  American  Institute  of  Chemical  Engineers,     8vo. 

Seven  volumes  now  ready.    Vol.  I.  to  VII.,  1908-1914.  ..  .8vo,  each,  "^6   jo 

Traverse  Tables.     (Science  Series  No.  115.) i6mo,  o  50 

morocco,  i  00 

Treiber,   E.     Foundry   Machinery.     Trans,   by   C.   Salter iimo,  i  25 

TrinkSjW.,  and  Housum,  C.     Shaft  Governors.     (Science  Series  No.  122.J 

i6:no,  0  50 

Trowbridge,  W.  P.     Turbine  Wheels.     (Science  Series  No.  44. ; .  .  i6mo,  0  50 

Tucker,  J.  H.     A  Manual  of  Sugar  Analysis 8vo,  3  50 

Turmer,  P.  A.     Treatise  on  Roll-turning.     Trans,  by  J.  B.  Pearse. 

8vo,  text  and  folio  atlas,  10  00 
Tumbull,  Jr.,  J.,  and  Robinson,  S.  W.     A  Treatise  on  the  Compound 

Steam-engine.     ( Science  Series  No.  8.) i6mo, 

Turrill,  S.  M.     Elementary  Course  in  Perspective i2mo,  *i  25 

Twyford,   H.   B.      Purchasing 8vo,  *3  00 

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Vacher,  F.     Food  Inspector's  Handbook i2mo,  *3  00 

Van  Nostrand's  Chemical  Annual.     Third  issue  1913.  ..  .leather,  lamo,  "2  50 

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Wabner,  R.     Ventilation  in  Mines.     Trans,  by  C.  Salter 8vo,  '4  50 

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Wagner,  E.     Preserving  Fruits,  Vegetables,  and  Meat i2mo,  *2  50 

Waldram,  P.  J.     Principles  of  Structural  Mechanics i2mo,  *3  00 

Walker,  F.     Aerial  Navigation 8vo,  2  00 

Dynamo  Building.     (Science  Series  No.  98.) i6mo,  o  50 

"/alker,  F.     Electric  Lighting  for  Marine  Engineers 8vo,  2  00 

Walker,  J.     Organic  Chemistry  for  Students  of   Medicine 8vo,  *2  50 

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Wilcox,  R.  M.      Cantilever  Bridges.     (Science  Series  No.  25.).  ..  .i6nio,  o  50 

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V.^'isser,  Lieut.  J.  P.     Explosive  Materials.      (Science   Series  No.   70.) 

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Wood,  De  V,     Luminiferous  Aether.     (Science  Series  No.  85)...i6mo,  o  50 
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Worden,  E.  C.     The  Nitrocellulose  Industry.     Two  Volumes 8vo,  *io  00 

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Wright,  A.  C.     Analysis  of  Oils  and  Allied  Substances 8vo,  ''3  50 

Simple  Method  for  Testing  Painters'  Materials 8vo,  ''2  50 

Wright,   F.  W.     Design  of  a   Condensing   Plant i2mo,  *i  50 

Vhight,   H.   E.     Handy   Book  for   Brewers 8vo,  *5  00 

Wright,  J.     Testing,  Fault  Finding,  etc.,  for  Wiremen.     ( Installation 

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Wright,  T.  W.     Elements   of  Mechanics 8vo,  *2  50 

Wright,  T.  W.,  and  Hayford,  J.  F.    Adjustment  of  Observations.  ..8vo,  *3  00 

Young,  J.  E.     Electrical  Testing  for  Telegraph  Engineers 8vo,  4  00 

Zahner,  R.     Transmission  of  Power.     ( Science  Series  No.  40. ) .  .  i6mo, 

Zeidler,  J.,  and  Lustgarten,  J.     Electric  Arc  Lamps 8vo,  *2  00 

Zeuner,  A.     Technical  Thermodynamics.     Trans,  by  J.  F.  Klein.     Two 

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Zipser,  J.    Textile  Raw  Materials.    Trans,  by  C.  Salter 8vo,  -5  00 

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